AGREEMENT AND PLAN OF MERGER

                                      AMONG

                          WEATHER SERVICES CORPORATION,

                      DATA TRANSMISSION NETWORK CORPORATION

                                       and

                        ABRY BROADCAST PARTNERS II, L.P.



                                      DATED

                                November 12, 1998


                                                        
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                                TABLE OF CONTENTS


ARTICLE I

THE MERGER....................................................................1
1A.      Formation of Merger Sub.  ...........................................1
1B.      General..............................................................1
1C.      Effect on WSC Share Equivalents......................................1
1D.      Certificate of Incorporation.........................................2
1E.      Bylaws...............................................................2
1F.      Board of Directors and Officers......................................2
1G.      Name.................................................................2
1H.      Exchange Procedures..................................................2
1I.      No Further Rights; Transfer of WSC Stock.............................2

ARTICLE  II

MERGER CONSIDERATION AND CLOSING..............................................3
2A.      Merger Consideration.................................................3
2B.      Deliveries at the Closing............................................3
2C.      Closing..............................................................3
2D.      Other Closing Transactions...........................................4

ARTICLE III

REPRESENTATIONS AND WARRANTIES OF WSC.........................................4
3A.      Existence and Good Standing..........................................4
3B.      Corporate Power; Authorization; Enforceable Obligations..............4
3C.      No Defaults..........................................................4
3D.      Litigation...........................................................5
3E.      Brokers..............................................................5
3F.      Capital Stock and Related Matters....................................5
3G.      Subsidiaries; Investments.  .........................................5
3H.      Financial Statements.................................................5
3I.      Accounts Receivable..................................................6
3J.      No Material Adverse Change...........................................6
3K.      Absence of Certain Developments......................................6
3L.      Assets...............................................................7
3M.      Tax Matters..........................................................7
3N.      Contracts and Commitments............................................7
3O.      Intellectual Property Rights.........................................8
3P.      Insurance............................................................9
3Q.      Employees............................................................9
3R.      Compliance with Laws.................................................9

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3S.      Employee Benefits....................................................9
3T.      Books of Account....................................................10
3U.      Software............................................................10
3V.      Director Action.....................................................10
3W.      Net Book Deficit....................................................10

ARTICLE IV

REPRESENTATIONS AND WARRANTIES OF ABRY.......................................11
4A.      Existence and Good Standing.........................................11
4B.      Limited Partnership Power; Authorization; Enforceable Obligations...11
4C.      No Defaults.........................................................11
4D.      Litigation..........................................................11
4E.      Brokers.............................................................12

ARTICLE V

REPRESENTATIONS AND WARRANTIES OF
DTN AND THE MERGER SUB.......................................................12
5A.      Incorporation.......................................................12
5B.      Corporate Action....................................................12
5C.      No Defaults.........................................................12
5D.      Brokers.............................................................13
5E.      Litigation..........................................................13

ARTICLE VI

COVENANTS OF WSC AND ABRY....................................................13
6A.      Maintenance of WSC Business until the Commencement Time.............13
6B.      Confidential Information............................................14
6C.      Efforts to Consummate...............................................14
6D.      Non-Solicitation....................................................14
6E.      Non-Competition.....................................................15
6F.      Confidentiality.....................................................15

ARTICLE VII

COVENANTS OF DTN AND THE MERGER SUB..........................................15
7A.      Confidential Information............................................15
7B.      Efforts to Consummate...............................................15
7C.      Continued Employment................................................16

ARTICLE VIII

CONDITIONS TO THE OBLIGATIONS OF WSC
AND WSC STOCKHOLDERS AT THE CLOSING..........................................16


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8A.      Representations, Warranties, Covenants..............................16
8B.      Sufficient Funds to Satisfy Obligations.............................17
8C.      DTN Legal Opinion...................................................17
8D.      Other...............................................................17

ARTICLE IX

CONDITIONS TO THE OBLIGATIONS OF DTN AND
THE MERGER SUB AT THE CLOSING................................................17
9A.      Representations, Warranties, Covenants..............................17
9B.      WSC Legal Opinion...................................................18
9C.      ABRY Legal Opinion..................................................18
9D.      Other...............................................................18

ARTICLE X

PRECLOSING COVENANTS.........................................................18
10A.     Public Announcements................................................18
10B.     WSC Stockholder Meeting.............................................18
10C.     Management and Consulting Agreement.................................18

ARTICLE XI

TERMINATION..................................................................20
11A.     Termination.........................................................20
11B.     Effect of Termination...............................................20
11C.     Waiver of Right to Terminate........................................20

ARTICLE XII

ADDITIONAL AGREEMENTS; COVENANTS AFTER CLOSING...............................21
12A.     Survival of Representations and Warranties..........................21
12B.     Mutual Assistance and Records.......................................21
12C.     Access..............................................................21
12D.     Expenses............................................................21
12E.     Taxes; Recording Charges............................................21
12F.     Indemnification  by ABRY............................................21

ARTICLE XIII

MISCELLANEOUS................................................................23
13A.     Amendment and Waiver................................................23
13B.     Notices.............................................................24
13C.     Assignment..........................................................25
13D.     Severability........................................................25
13E.     No Strict Construction..............................................25


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13F.     Captions............................................................25
13G.     Third Parties.......................................................25
13H.     Complete Agreement..................................................25
13I.     Counterparts........................................................25
13J.     Governing Law.......................................................26
13K.     Specific Performance................................................26


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                          AGREEMENT AND PLAN OF MERGER


      THIS  AGREEMENT  AND PLAN OF MERGER (the  "Agreement")  is entered into on
November 12, 1998 by and among Weather  Services  Corporation,  a  Massachusetts
corporation  ("WSC"),   Data  Transmission   Network  Corporation,   a  Delaware
corporation  ("DTN"),  on behalf of itself and a  subsidiary  to be formed by it
pursuant to Section 1A below,  and ABRY Broadcast  Partners II, L.P., a Delaware
limited partnership ("ABRY").

      WHEREAS,  WSC is engaged  in the  business  of  compiling,  marketing  and
distributing  meteorological  information for the purpose of weather forecasting
(the "WSC Business"); and

      WHEREAS,  DTN desires to acquire  the  capital  stock of WSC by means of a
merger; and

      NOW,  THEREFORE,  FOR GOOD AND  VALUABLE  CONSIDERATION,  the  receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

                                    ARTICLE I

                                   THE MERGER

      1A.  Formation of Merger Sub. On or prior to November  18, 1998,  DTN will
form a wholly-owned Subsidiary which will be a Massachusetts  corporation.  Such
Subsidiary  will be the "Merger  Sub"  referred to in this  Agreement.  DTN will
cause such  Subsidiary  to become a party to this  Agreement  by  executing  and
delivering to WSC a counterpart thereof.

      1B. General.  Upon and subject to the terms and conditions  stated in this
Agreement,  on the Closing Date,  effective as of the Effective Time, the Merger
Sub will merge with and into WSC in accordance  with the terms and conditions of
this  Agreement.  WSC will be the  corporation  which  survives such merger (the
"Merger")  and in such  capacity is sometimes  referred to in this  Agreement as
"Post-Merger WSC."

      1C.  Effect  on WSC Share  Equivalents.  Immediately  after  the  Closing,
subject to the terms and  conditions  of this  Agreement  (1) the Merger will be
effected  by  filing  Articles  of  Merger  with the  Secretary  of the State of
Massachusetts;  (2) each WSC Share Equivalent outstanding at the Effective Time,
by said occurrence and with no further action on the part of the holder thereof,
will be  transformed  and  converted  into  the  right  to  receive  the  Merger
Consideration  for such WSC Share  Equivalent,  without  interest or any similar
payment  thereon or with respect  thereto,  upon  surrender  of the  certificate
representing  such WSC Share  Equivalent;  (3) each share of common stock of the
Merger Sub  outstanding  immediately  prior to the Effective  Time will, by said
occurrence  and with no  further  action on the part of the holder  thereof,  be
transformed and converted into one share of common stock of Post-Merger  WSC, so
that  immediately  thereafter  DTN will be the sole and  exclusive  owner of all
equity  securities of Post-Merger WSC; and (4) Post-Merger WSC will be the owner

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of the business, assets, rights, privileges,  immunities, powers, franchises and
other attributes of WSC and the Merger Sub.

      1D.  Certificate of  Incorporation.  Immediately after the Effective Time,
the certificate of  incorporation  of Post-Merger WSC will be the certificate of
incorporation of the Merger Sub as in effect  immediately prior to the Effective
Time.

      1E.  Bylaws.   Immediately   after  the  Effective  Time,  the  bylaws  of
Post-Merger  WSC will be the bylaws of the  Merger Sub as in effect  immediately
prior to the Effective Time.

      1F. Board of Directors and  Officers.  The board of directors and officers
of the Merger Sub  immediately  prior to the Effective Time will be the board of
directors and the officers,  respectively,  of Post-Merger WSC immediately after
the Effective  Time, and such  individuals  will serve in such positions for the
respective  terms in accordance  with the bylaws of Post-Merger  WSC until their
respective successors are elected and qualified.

      1G. Name. The name of Post-Merger WSC will be designated by DTN.

      1H. Exchange Procedures. At or after the Closing, each holder of record of
WSC Share  Equivalents  will deliver to  Post-Merger  WSC for  cancellation  the
certificate(s)   representing   such  WSC  Share   Equivalents   (the  "Old  WSC
Certificates").  Upon  surrender of any Old WSC  Certificate  for  cancellation,
subject  to the  provisions  of this  Agreement,  (a) the holder of such Old WSC
Certificate will receive in exchange  therefor the Merger  Consideration for the
WSC Share Equivalents represented by such Old WSC Certificate,  and (b) such Old
WSC  Certificate  will be canceled.  Until  surrendered as  contemplated by this
Section 1H, each Old WSC  Certificate  will, at and after the Effective Time, be
deemed to represent  only the right to receive,  upon  surrender of such Old WSC
Certificate,  the Merger Consideration for the WSC Share Equivalents represented
by such Old WSC Certificate. Each share of common stock of the Merger Sub issued
and outstanding immediately prior to the Effective Time shall continue to be one
share of common stock of the surviving corporation, with the same rights, powers
and privileges as such share of common stock of the Merger Sub immediately prior
to the Effective Time.

      1I. No Further  Rights;  Transfer of WSC Stock.  The Merger  Consideration
paid for any WSC Share Equivalent in accordance with the terms of this Agreement
will be deemed to have been paid in full  satisfaction of all rights  pertaining
to such WSC Share Equivalent. At the Effective Time, the stock transfer books of
WSC will be closed and no transfer of WSC Share  Equivalents  will thereafter be
made.

                                   ARTICLE II

                        MERGER CONSIDERATION AND CLOSING

      2A. Merger Consideration.

          (1) Amount for all WSC Share Equivalents in the Aggregate.  Subject to
      the terms and conditions of this Agreement, the "Merger Consideration" for

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      all  WSC  Share   Equivalents  shall  be  warrants  (the  "DTN  Warrants")
      representing  the right to purchase  twenty  thousand  (20,000)  shares of
      common  stock  of DTN in the  aggregate  at a price  of $34 per  share  in
      accordance  with the  terms and  conditions  of one or more  Common  Stock
      Purchase  Warrant  certificates  substantially  in the  form  attached  as
      Exhibit 2A hereto, which will be issued solely to accredited investors (as
      that term is defined in the rules  promulgated  pursuant to the Securities
      Act of 1933,  as amended).  The DTN Warrants will be issued on the Closing
      Date and will expire on the seventh anniversary of the Closing Date.

          (2) Amount for any  Particular WSC Share  Equivalent.  With respect to
      any particular WSC Share Equivalent,  the "Merger Consideration" means the
      portion  of  the  aggregate  Merger   Consideration   for  all  WSC  Share
      Equivalents which is equal to the amount that the holder of such WSC Share
      Equivalent would receive in respect of such WSC Share Equivalent if:

                (a) all WSC Rights  (other than WSC's Series C Preferred  Stock)
          outstanding  immediately  prior to the Effective  Time were  converted
          into or exercised or  exchanged  for WSC Shares to the fullest  extent
          permitted  by the terms of such WSC Rights,  immediately  prior to the
          Effective Time, and

                (b) WSC thereafter  distributed to the holders of the WSC Shares
          outstanding  immediately  prior to the  Effective  Time (after  giving
          effect to the  conversions,  exercises  and  exchanges  referred to in
          clause (a) above),  in accordance  with the provisions of its articles
          of organization, an amount equal to the aggregate Merger Consideration
          for the WSC Share Equivalents,

      reduced,  in the case of any WSC  Right,  by the  exercise  price (if any)
      payable  upon the  exercise of such WSC Right as  described  in clause (a)
      above. For purposes of this Section 2A(2), each DTN Warrant will be deemed
      to have a value of $1.00.

      2B.  Deliveries  at the  Closing.  All actions on the Closing Date will be
deemed to occur  simultaneously,  and no document or payment to be  delivered or
made on the Closing  Date will be deemed to be  delivered or made until all such
documents and payments are delivered or made to the reasonable  satisfaction  of
WSC, the Merger Sub and their respective legal counsel.

      2C. Closing.  Subject to the conditions  contained in this Agreement,  the
closing of the transactions  contemplated by this Agreement (the "Closing") will
occur at the offices of Kirkland & Ellis,  in New York,  New York, at 10:00 a.m.
on the  first  business  day after all  conditions  precedent  set forth in this
Agreement  have been satisfied or at such other time and/or place as the parties
shall agree, but in no event later than December 11, 1998 (the "Closing Date").

      2D. Other Closing Transactions.  At the Closing,  Post-Merger WSC will pay
in full all  principal  and interest  owing under the Loan  Agreements as of the
Closing Date and all accrued  management fees under the Management  Agreement as
of the  Commencement  Time  and  expense  reimbursements  owed to ABRY as of the
Closing Date, after giving effect to the forgiveness and annulment  described in
the  following  sentence.  At the  Closing,  the  Management  Agreement  will be
terminated  and all  other  liabilities  of WSC to ABRY  will  be  forgiven  and

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annulled,  to the extent that the existence of such liabilities  would cause the
net  book  deficit  of WSC,  as  defined  in  Section  3W,  to be  greater  than
$3,000,000.  In addition,  at the Closing,  Post-Merger WSC will pay to Peter R.
Leavitt  the sum of  $102,105  and to Michael  S.  Leavitt  the sum of  $42,292,
representing  the full amount of all salaries,  severance or  reimbursement  for
expenses  accrued  or  owing  to  Peter  R.  Leavitt  and  Michael  S.  Leavitt,
respectively. DTN will cause Post-Merger WSC to pay all of the foregoing amounts
at the Closing.


                                   ARTICLE III

                      REPRESENTATIONS AND WARRANTIES OF WSC

      In order to induce DTN to enter into this  Agreement,  WSC  represents and
warrants to DTN and to the Merger Sub that,  except as set forth on the attached
Exceptions Schedule:

      3A.  Existence and Good  Standing.  WSC is a corporation  duly  organized,
validly existing and, where  applicable,  in good standing under the laws of the
Commonwealth of Massachusetts. WSC has the power and authority to own, lease and
operate its property and to carry on its business as now being  conducted and to
own or lease  the  assets  owned  or  leased  by it.  WSC is duly  qualified  or
licensed,  or otherwise in good standing, to do business in each jurisdiction in
which it owns or leases properties,  conducts operations or maintains a stock of
goods,  with full power and  authority  to carry on the  business in which it is
engaged and to execute and deliver and carry out the  transactions  contemplated
by this Agreement.

      3B. Corporate Power;  Authorization;  Enforceable Obligations.  Subject to
obtaining  requisite  approval  of its  stockholders  (which  approval  will  be
obtained prior to the Closing),  WSC has, and on the Closing Date will have, the
corporate power, authority and legal right to execute,  deliver and perform this
Agreement,  and on the Closing Date the execution,  delivery and  performance of
this Agreement by WSC will have been duly authorized by all necessary  corporate
and shareholder action. This Agreement has been, and on the Closing Date the WSC
Closing  Documents  to which  WSC will be a party  will be,  duly  executed  and
delivered on behalf of WSC by its duly authorized officers or representatives or
attorney-in-fact,  and this Agreement  constitutes,  and on the Closing Date the
WSC Closing  Documents to which WSC will be a party when  executed and delivered
will constitute,  the legal, valid and binding  obligations of WSC,  enforceable
against WSC in accordance with their respective terms,  subject to the effect of
applicable  bankruptcy,  insolvency,   reorganization,   fraudulent  conveyance,
arrangement,  moratorium  or similar  laws  affecting  the  rights of  creditors
generally and the availability of equitable remedies.

      3C. No Defaults. On the Closing Date (after giving effect to all approvals
and consents which have been obtained) neither the execution and delivery by WSC
of this  Agreement,  nor the  consummation  by WSC of the  Merger  or the  other
transactions  contemplated by this Agreement to be consummated by WSC,  requires
any consent under, will constitute, or, with the giving of notice or the passage
of time or both, would constitute,  a material violation of or would conflict in
any material  respect  with or result in any material  breach of or any material
default  under,  or will  result in the  creation  of any Lien  (other  than any
Permitted Encumbrance) under, any of the terms, conditions, or provisions of any
law,  rule  or  regulation  of any  governmental  authority,  or any  agreement,

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instrument,  license or permit, or of any order,  writ,  injunction or decree to
which WSC is subject, or of the certificate of incorporation or bylaws of WSC.

      3D.  Litigation.  On the date of this  Agreement,  there is no  litigation
pending by or against, or to the knowledge of WSC threatened against,  WSC which
interferes  in a material  respect  with,  or could  reasonably  be  expected to
interfere  in a  material  respect  with,  (a) the  WSC  Business  as  presently
conducted  or (b) the  ability of WSC or the WSC  Stockholders  to carry out the
transactions  contemplated to be carried out by them pursuant to this Agreement,
and at the Commencement Time, no such pending or threatened litigation will have
or will reasonably be expected to have such effect.

      3E.  Brokers.  There is no broker or finder or other Person who would have
any valid claim against WSC for a commission or brokerage fee in connection with
this  Agreement  or the  transactions  contemplated  hereby  as a result  of any
agreement  or  understanding  of, or action taken by, WSC, the Merger Sub or any
Affiliate of any of them.

     3F.  Capital Stock and Related  Matters.  As of the Closing,  WSC shall not
have  outstanding any securities  convertible or exchangeable  for any shares of
its  capital  stock,  nor shall it have  outstanding  any  rights or  options to
subscribe  for or to  purchase  its  capital  stock or any  stock or  securities
convertible into or exchangeable  for its capital stock. As of the Closing,  WSC
shall not be subject to any  obligation  (contingent or otherwise) to repurchase
or otherwise  acquire or retire any shares of its capital stock or any warrants,
options or other rights to acquire its capital stock. As of the Closing,  all of
the  outstanding  shares of WSC's capital stock shall be validly  issued,  fully
paid and nonassessable.

     3G.  Subsidiaries;  Investments.  WSC does not own or hold  any  rights  to
acquire any shares of stock or any other security, interest or investment in any
other Person, and WSC has never had any Subsidiary.

     3H. Financial  Statements.  Attached hereto as Exhibit 3H are the following
financial statements:

     (i) the  balance  sheet of WSC as of  December  31,  1997  and the  related
statements  of income and cash flows for the  twelve-month  period  then  ended,
reviewed by its independent accounting advisors, Price Waterhouse Coopers; and

     (ii) the  unaudited  balance  sheet of WSC as of  September  30,  1998 (the
"Latest Balance Sheet"), for the nine-month period then ended.

Each of the  foregoing  financial  statements  (including in all cases the notes
thereto,  if any) was accurate  and complete in all material  respects as of the
date thereof,  is consistent with the books and records of WSC (which,  in turn,
are accurate and complete) and has been  prepared in accordance  with  generally
accepted accounting  principles,  consistently  applied ("GAAP") (except, in the
case of the Latest  Balance  Sheet,  for the absence of  footnotes  and year-end
adjustments).

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     3I. Accounts Receivable. The uncollected accounts receivable of WSC arising
from the WSC Business prior to the Commencement Time (the "Accounts Receivable")
will be valid and genuine and will have arisen solely out of bona fide sales and
deliveries of goods, the performance of services and other business transactions
in the ordinary course of business  consistent with past practice.  The Accounts
Receivable will not be subject to valid defenses,  set-offs or counterclaims and
will be  collectible  during the period  ending  eleven months after the Closing
Date at the full recorded amount thereof.

     3J. No Material Adverse Change. Since the date of the Latest Balance Sheet,
there has been no change or event which has had a Material Adverse Effect.

     3K. Absence of Certain Developments.

     (i) Except as expressly  contemplated by this Agreement,  since the date of
the Latest Balance Sheet, WSC has not:

                (a)  declared  or made any  payment or  distribution  of cash or
          other property to its  stockholders  with respect to its capital stock
          or other equity  securities or purchased or redeemed any shares of its
          capital stock or other equity securities;

                (b) sold,  assigned or transferred  any of its material  assets,
          except in the ordinary  course of  business,  or canceled any debts or
          claims;

                (c) sold,  assigned or  transferred  any  material  Intellectual
          Property Rights;

                (d)  suffered any  extraordinary  losses or waived any rights of
          value;

                (e) made  capital  expenditures  or  commitments  therefor  that
          aggregate in excess of $100,000;

                (f) made any  charitable  contributions  or pledges in excess of
          $2,000 in the aggregate; or

                (g) suffered any damage,  destruction or casualty loss exceeding
          in the aggregate $100,000, whether or not covered by insurance.

      (ii) WSC has not at any time made any payments for political contributions
or made any bribes, kickback payments or other illegal payments.

      3L.  Assets.  WSC has good and marketable  title to, or a valid  leasehold
interest  in, the  material  properties  and assets  used by it,  located on its
premises or shown on the Latest Balance Sheet or acquired  thereafter,  free and
clear of all consensual  Liens,  except for properties and assets disposed of in
the ordinary  course of business  since the date of the Latest Balance Sheet and
except for Liens  disclosed on the Latest  Balance  Sheet  (including  any notes
thereto). WSC's buildings,  equipment and other material tangible assets are fit

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for use in the ordinary  course of business.  WSC owns, or has a valid leasehold
interest in, all assets  necessary for the conduct of its respective  businesses
as presently conducted and as presently proposed by WSC to be conducted.

      3M. Tax Matters.

          (1) WSC has filed all  material  tax  returns  which it is required to
      file under  applicable  laws and  regulations;  all such tax  returns  are
      complete  and  correct in all  material  respects;  WSC has not waived any
      statute  of  limitations  with  respect  to any  taxes  or  agreed  to any
      extension of time with respect to any tax  assessment or  deficiency;  the
      federal income tax returns of WSC have been audited and closed for all tax
      years through  December 31, 1992;  WSC has received no notice and does not
      have  reason to  believe  that any  foreign,  federal,  state or local tax
      audits or administrative or judicial  proceedings are pending or are being
      conducted with respect to WSC, no  information  related to tax matters has
      been requested by any foreign,  federal,  state or local taxing  authority
      and no  written  notice  indicating  an  intent  to open an audit or other
      review has been received by WSC from any foreign,  federal, state or local
      taxing authority; and there are no material unresolved questions or claims
      concerning WSC's tax liability with any foreign,  federal,  state or local
      taxing authority.

          (ii) WSC has not made an  election  under  ss.341(f)  of the  Internal
      Revenue Code of 1986, as amended (the  "Code").  WSC is not liable for the
      Taxes of another Person under (a) Treas.  Reg. ss. 1.1502-6 (or comparable
      provisions  of  state,  local or  foreign  law),  (b) as a  transferee  or
      successor,  (c) by contract or  indemnity or (d)  otherwise.  WSC is not a
      party to any tax  sharing  agreement.  WSC has not made any  payments,  is
      obligated  to make  payments  or is a party  to an  agreement  that  could
      obligate it to make any payments that would not be  deductible  under Code
      ss.280G.

      3N.  Contracts and Commitments.

          (ii) The attached  Exceptions Schedule lists all material contracts to
      which WSC is a party.

          (ii)  To  WSC's  knowledge,  all  of  the  contracts,  agreements  and
      instruments  listed on the  Exceptions  Schedule  are valid,  binding  and
      enforceable in accordance with their respective terms. Except as would not
      have a Material  Adverse  Effect:  (a) WSC has performed  all  obligations
      required  to be  performed  by it  under  the  contracts,  agreements  and
      instruments listed on the Exceptions  Schedule and is not in default under
      or in breach of nor in receipt of any claim of default or breach under any
      contract,  agreement or instrument listed on the Exceptions Schedule;  (b)
      no event has  occurred  which  with the  passage  of time or the giving of
      notice or both would result in a default, breach or event of noncompliance
      by  WSC  under  any  contract,  agreement  or  instrument  listed  on  the
      Exceptions  Schedule;  (c) WSC does not have any  present  expectation  or
      intention of not fully performing all such  obligations;  and (d) WSC does
      not have  knowledge  of any  breach  or  anticipated  breach  by the other
      parties to any contract, agreement, instrument or commitment listed on the
      Exceptions Schedule.

                                       12
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<PAGE>



          (iii) DTN's  special  counsel has been supplied with or has had access
      to a true and  correct  copy of each of the  written  instruments,  plans,
      contracts and agreements  and an accurate  description of each of the oral
      arrangements,  contracts  and  agreements  which  are  referred  to on the
      Exceptions  Schedule,  together  with  all  amendments,  waivers  or other
      changes thereto.

      3O.  Intellectual Property Rights.

          (i) WSC owns all right, title and interest to, or has the right to use
      pursuant to a valid license,  all  Intellectual  Property Rights necessary
      for the  operation of the business of WSC as  presently  conducted  and as
      presently proposed to be conducted (the "Required Intellectual Property"),
      free and  clear of all  consensual  Liens.  Since  the date of the  Latest
      Balance Sheet, the loss or expiration of any  Intellectual  Property Right
      or related group of Intellectual  Property Rights owned or used by WSC has
      not had a Material  Adverse Effect,  and no such loss or expiration is, to
      WSC's  knowledge,  threatened  or  pending.  WSC has taken all  reasonably
      necessary and desirable  actions to maintain and protect the  Intellectual
      Property Rights which it owns.

          (ii)  There  have  been no  claims  made  against  WSC  asserting  the
      invalidity,  misuse  or  unenforceability  of  any  Required  Intellectual
      Property, and, to WSC's knowledge,  there are no grounds for the same. WSC
      has not  received  any  notices  of,  and is not aware of any facts  which
      indicate a likelihood  of, any  infringement  or  misappropriation  by, or
      conflict  with,  any third  party with  respect to  Required  Intellectual
      Property  (including,  without limitation,  any demand or request that WSC
      license any rights from a third party),  the conduct of WSC's business has
      not infringed,  misappropriated  or conflicted with and does not infringe,
      misappropriate or conflict with any Intellectual  Property Rights of other
      Persons, nor would any future conduct as presently  contemplated infringe,
      misappropriate or conflict with any Intellectual  Property Rights of other
      Persons, in each case to the extent that the results of such conduct would
      cause a Material  Adverse Effect.  To WSC's  knowledge,  the  Intellectual
      Property  Rights  owned by or  licensed  to WSC  have not been  infringed,
      misappropriated   or  conflicted  by  other  Persons.   The   transactions
      contemplated  by this  Agreement  shall  have no  adverse  effect on WSC's
      right, title and interest in and to the Required Intellectual Property.

          (iii) The Exceptions Schedule lists all patents,  trademarks,  service
      marks,  trade names,  and  copyrights  used in the WSC  Business  that are
      registered by WSC or for which applications for registration are pending.

      3P. Insurance. WSC is not in default with respect to its obligations under
any insurance policy maintained by it.

      3Q.  Employees.  WSC has complied with all laws relating to the employment
of labor (including,  without limitation,  provisions thereof relating to wages,
hours,  equal  opportunity,  collective  bargaining  and the  payment  of social
security and other taxes),  and WSC is not aware that it has any labor relations
problems  (including,  without  limitation,  any union organization  activities,
threatened or actual strikes or work stoppages or grievances).  Neither WSC nor,


                                       13
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to  WSC's  knowledge,  any of  its  employees  is  subject  to  any  noncompete,
nondisclosure,  confidentiality,  employment,  consulting or similar  agreements
relating  to,  affecting  or in conflict  with the present or proposed  business
activities of WSC, except for agreements  between WSC and its present and former
employees.  WSC has not  employed  more than  one-hundred  (100)  employees on a
full-time basis at any given time since March 1, 1998.

      3R. Compliance with Laws. WSC has not violated any law or any governmental
regulation  or  requirement  which  violation  has had or would  have a Material
Adverse Effect,  and WSC has not received  notice of any such violation.  WSC is
not  subject  to,  nor has  reason to  believe  it may  become  subject  to, any
liability (contingent or otherwise) or corrective or remedial obligation arising
under  any  Environmental  and  Safety  Requirements  which  has  had  or  would
reasonably be expected to have a Material  Adverse Effect.  Without limiting the
generality  of the  foregoing,  (i) WSC has obtained  all permits,  licenses and
authorizations  required under,  and have complied with, all  Environmental  and
Safety  Requirements,  (ii) no notice has been  received  by WSC  regarding  any
violation  of, or any claim,  liability  or  corrective  or remedial  obligation
under,  any  Environmental  and  Safety  Requirements  and  (iii)  no  facts  or
circumstances exist with respect to the past or present operations or facilities
of WSC which would give rise to a liability or corrective or remedial obligation
under any Environmental and Safety Requirements.

      3S.  Employee Benefits.

          (1) The Exceptions  Schedule contains an accurate and complete list of
      (a) each "employee  benefit plan" (as such term is defined in Section 3(3)
      of the  Employee  Retirement  Income  Security  Act of  1974,  as  amended
      ("ERISA"))  maintained  by WSC and (b)  each  other  retirement,  savings,
      thrift, deferred compensation, severance, stock ownership, stock purchase,
      stock   option,    performance,    bonus,   incentive,   fringe   benefit,
      hospitalization or other medical, disability, life or other insurance, and
      any other welfare benefit maintained by WSC for the benefit of any present
      or former  employee,  officer or director of WSC, other than any such plan
      which is solely  discretionary.  Each such item  listed on the  Exceptions
      Schedule is  referred  to herein as a "Benefit  Plan." None of the Benefit
      Plans is a defined benefit pension plan or a Multi-employer plan.

          (2) Each  Benefit  Plan that is  intended to be  qualified  within the
      meaning of Section  401(a) of the Code has received a  determination  from
      the Internal  Revenue  Service  that such Benefit Plan is qualified  under
      Section  401(a) of the Code,  and nothing has  occurred  since the date of
      such  determination  that could adversely affect the qualification of such
      Benefit Plan.

          (3)  Except  as would not have a  Material  Adverse  Effect:  (a) each
      Benefit Plan has been  maintained,  funded and  administered in compliance
      with its respective terms and in compliance in all material  respects with
      all applicable laws and regulations, including ERISA and the Code; and (b)
      there are no pending  or  threatened  actions,  suits,  investigations  or
      claims with  respect to any Benefit  Plan (other than  routine  claims for
      benefits)  which  could  result in  liability  to WSC  (whether  direct or
      indirect). WSC has complied with the health care continuation requirements
      of Part 6 of Title I of ERISA.


                                       14
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<PAGE>




      3T. Books of Account.  The books,  records and accounts of WSC  maintained
with respect to the WSC Business  accurately and fairly reflect, in all material
respects, the transactions and the assets and liabilities of WSC with respect to
the WSC Business.  WSC has not engaged in any material  transaction with respect
to its business operations,  maintained any bank account for the WSC Business or
used any of the  funds of WSC in the  conduct  of the WSC  Business  except  for
transactions,  bank  accounts and funds which have been and are reflected in the
normally maintained books and records of the WSC Business.

      3U. Software.  Any software used by WSC in the conduct of the WSC Business
and not licensed from third parties has been developed entirely by the employees
of WSC during the time they were  employees only of WSC and does not include any
inventions  of the  employees  made  prior to the  time  such  employees  became
employees of WSC nor any intellectual  property of any previous employer of such
employee.  With  respect to any  software  used by WSC in the conduct of the WSC
Business and licensed by WSC for such use from third parties, WSC is in material
compliance with obligations arising under all related licensing  agreements with
such third parties.

      3V.  Director  Action.  The Board of  Directors  of WSC (at a meeting duly
called and held or otherwise by valid  consent) has by the requisite vote of all
directors  present (a)  determined  that the Merger is advisable and in the best
interests of WSC and the WSC  Stockholders,  (b) approved this Agreement and the
transactions  contemplated hereby, and (c) directed that the Merger be submitted
for consideration by the WSC Stockholders.

      3W. Net Book Deficit.  As of the Commencement Time, the "net book deficit"
of WSC will not be greater than $3,000,000; provided that the "net book deficit"
of WSC at any time means the amount by which  WSC's  total  liabilities  at such
time  exceeds the amount of WSC's total  assets at such time,  in each case,  as
determined  in  accordance  with  GAAP  (except  for  the  absence  of  year-end
adjustments).  For purposes of  determining  the net book deficit,  all Accounts
Receivable will be valued at their  respective face amounts,  without  allowance
for uncollectible or doubtful  accounts.  In the event that the net book deficit
is greater than $3,000,000 at the Commencement Time, the amount that Post-Merger
WSC will pay to ABRY at  Closing  pursuant  to  Section 2D will be reduced in an
amount equal to the amount by which the net book deficit exceeds $3,000,000.


                                   ARTICLE IV

                     REPRESENTATIONS AND WARRANTIES OF ABRY


      In order to induce DTN to enter into this  Agreement,  ABRY represents and
warrants to DTN and to the Merger Sub as follows:

      4A.  Existence  and Good  Standing.  ABRY is a  limited  partnership  duly
organized,  validly existing and, where  applicable,  in good standing under the
laws of the State of Delaware.  ABRY has the power and  authority to own,  lease
and operate its property and to carry on its business as now being conducted and
to own or lease the  assets  owned or leased by it.  ABRY is duly  qualified  or
licensed, or otherwise in good standing, to do business in each jurisdiction in

                                       15
                                    - 326 -
<PAGE>




which it owns or leases properties,  conducts operations or maintains a stock of
goods,  with full power and  authority  to carry on the  business in which it is
engaged and to execute and deliver and carry out the  transactions  contemplated
by this Agreement.

      4B. Limited  Partnership Power;  Authorization;  Enforceable  Obligations.
ABRY has the power,  authority  and legal right to execute,  deliver and perform
this  Agreement.  The execution,  delivery and  performance of this Agreement by
ABRY has been duly authorized by all necessary action by the limited partnership
and its partners.  This Agreement has been duly executed and delivered on behalf
of ABRY by its duly authorized officers or representatives or  attorney-in-fact,
and this Agreement constitutes the legal, valid and binding obligations of ABRY,
enforceable  against it in accordance  with its terms,  subject to the effect of
applicable  bankruptcy,  insolvency,   reorganization,   fraudulent  conveyance,
arrangement,  moratorium  or similar  laws  affecting  the  rights of  creditors
generally and the availability of equitable remedies.

      4C. No Defaults. On the Closing Date (after giving effect to all approvals
and consents  which have been  obtained)  neither the  execution and delivery by
ABRY of this Agreement,  nor the consummation by ABRY of the Merger or the other
transactions  contemplated by this Agreement to be consummated by ABRY, requires
any consent under, will constitute, or, with the giving of notice or the passage
of time or both, would constitute,  a material violation of or would conflict in
any material  respect  with or result in any material  breach of or any material
default  under,  or will  result in the  creation  of any Lien  (other  than any
Permitted Encumbrance) under, any of the terms, conditions, or provisions of any
law,  rule  or  regulation  of any  governmental  authority,  or any  agreement,
instrument,  license or permit, or of any order,  writ,  injunction or decree to
which ABRY is subject,  or of the  certificate of partnership or the partnership
agreement of ABRY.

      4D.  Litigation.  On the date of this  Agreement,  there is no  litigation
pending by or against,  or to the  knowledge of ABRY  threatened  against,  ABRY
which  interferes in a material respect with, or could reasonably be expected to
interfere  in a  material  respect  with,  (a) the  WSC  Business  as  presently
conducted or (b) the ability of WSC to carry out the  transactions  contemplated
to be carried out by them pursuant to this  Agreement,  and at the  Commencement
Time, no such pending or threatened  litigation  will have or will reasonably be
expected have such effect.

      4E.  Brokers.  There is no broker or finder or other Person who would have
any valid claim against WSC for a commission or brokerage fee in connection with
this  Agreement  or the  transactions  contemplated  hereby  as a result  of any
agreement  or  understanding  of, or action taken by, WSC, the Merger Sub or any
Affiliate of any of them.



                                       16
                                    - 327 -
<PAGE>




                                    ARTICLE V

                        REPRESENTATIONS AND WARRANTIES OF
                             DTN AND THE MERGER SUB

      DTN and the Merger Sub,  jointly and  severally,  represent and warrant as
follows:

      5A. Incorporation.  DTN is a corporation duly organized, validly existing,
and in good  standing (or has  comparable  active  status) under the laws of the
State of Delaware,  and DTN has the corporate  power and authority to enter into
and consummate the transactions  contemplated by this Agreement.  From and after
the time it is  formed,  the Merger Sub will be a  corporation  duly  organized,
validly  existing,  and in good standing (or has comparable active status) under
the laws of the Commonwealth of Massachusetts  and will have the corporate power
and authority to enter into and consummate the  transactions  contemplated to be
consummated by this Agreement.

      5B. Corporate Action.  Each action necessary to be taken by or on the part
of either DTN or the Merger Sub in connection with the execution and delivery of
this Agreement and the  consummation  of  transactions  contemplated  hereby and
necessary to make the same  effective  will be duly and validly taken by, and be
effective  at,  the time by which  such  action is  required  to be taken.  This
Agreement has been duly and validly authorized,  executed, and delivered by each
of DTN and the  Merger  Sub and  constitutes  a  valid  and  binding  agreement,
enforceable  against each of them in  accordance  with and subject to its terms,
subject  to the effect of  applicable  bankruptcy,  insolvency,  reorganization,
fraudulent  conveyance,  arrangement,  moratorium or similar laws  affecting the
rights of creditors generally and the availability of equitable remedies.

      5C. No Defaults. On the Closing Date (after giving effect to all approvals
and consents  which have been  obtained),  neither the execution and delivery by
DTN or the  Merger Sub of this  Agreement,  nor the  consummation  by DTN or the
Merger  Sub of the  Merger  and  the  other  transactions  contemplated  by this
Agreement, will constitute, or, with the giving of notice or the passage of time
or both,  would  constitute,  a material  violation of or would  conflict in any
material  respect  with or result  in any  material  breach  of or any  material
default under, any of the terms,  conditions,  or provisions of any law, rule or
regulation of any governmental  authority,  or any license or permit,  or of any
order, writ,  injunction or decree to which DTN or the Merger Sub is subject, or
of DTN's or the Merger Sub's  certificate of incorporation or by-laws or similar
organizational documents, or of any material contract,  agreement, or instrument
to which DTN or the  Merger  Sub is a party or by which DTN or the Merger Sub is
bound.

      5D. Brokers.  There is no broker or finder or other Person what would have
any valid  claim  against  DTN or against  the Merger  Sub for a  commission  or
brokerage fee in connection with this Agreement or the transactions contemplated
hereby as a result of any  agreement  or  understanding  of, or action taken by,
DTN, the Merger Sub or any Affiliate of any of them.

      5E.  Litigation.  On the date of this  Agreement,  there is no  litigation
pending by or  against,  or to DTN's or the Merger  Sub's  knowledge  threatened
against,  DTN or the Merger Sub which  interferes in a material respect with, or
could reasonably be expected to interfere in a material respect with the ability
of DTN or of the Merger  Sub to carry out the  transactions  contemplated  to be

                                       17
                                    - 328 -
<PAGE>

carried out by them pursuant to this Agreement and at the Commencement  Time, no
such pending or threatened  litigation  will have or will reasonably be expected
to have such effect.

      5F. Collection of Accounts  Receivable.  Following the Commencement  Time,
DTN and the Merger Sub shall use their  respective  best  efforts to collect any
and all Accounts  Receivable  provided that DTN and  Post-Merger WSC will not be
required  to use  greater  efforts  than  those  employed  by WSC  prior  to the
Commencement  Time. All collections from any Person who is a debtor with respect
to an  Account  Receivable  will be applied  in the  chronological  order of the
respective  due  dates of the  amounts  owing  by such  Person  to WSC,  DTN and
Post-Merger  WSC (i.e.,  to the oldest unpaid amount first),  unless such Person
indicates  in writing  that a payment is to be  applied  in  another,  specified
manner (in which  case such  payment  will be applied in the manner  specified).
From the Commencement Time and through the eleven months after the Closing Date,
none of DTN,  Post-Merger WSC or ABRY will directly or indirectly  encourage any
such debtor to specify that any payment by such debtor to any of them be applied
in any manner other than in the  chronological  manner  described  above. In the
event  that DTN or  Post-Merger  WSC  makes a claim  for  indemnification  under
Section 12F arising out of a breach of a representation or warranty set forth in
Section 3I, to the extent that any Accounts  Receivable remain uncollected after
eleven months  following the Closing Date, DTN and the Merger Sub will assign to
ABRY (for the  benefit of the WSC  Stockholders)  the right to collect  all such
uncollected  Accounts  Receivable  and to  exercise  all rights and  remedies in
connection  thereto.  DTN and the Merger Sub promptly will turn over to ABRY the
proceeds of all collections in respect of the Accounts Receivable received after
such eleven-month  period, and the net proceeds of such collections  received by
ABRY will constitute additional Merger Consideration.


                                   ARTICLE VI

                            COVENANTS OF WSC AND ABRY

      6A. Maintenance of WSC Business until the Commencement Time

          (1) Operation in Ordinary  Course . Until the  Commencement  Time, WSC
      will use reasonable  efforts to (a) continue to carry on the WSC Business,
      keep the books of account, records, and files of WSC, and realize upon the
      Accounts  Receivable of WSC, in the ordinary and usual course, in a manner
      which is consistent with its past  practices,  and (b) timely file (taking
      into account any  extensions of which WSC or any of its  Subsidiaries  may
      avail  itself)  federal,  state,  local and  foreign  Tax  Returns and Tax
      reports required to be filed by WSC or any of its Affiliates.

          (2) Access  Generally.  From time to time at the  request of DTN,  WSC
      will give or cause to be given to the  officers,  employees,  accountants,
      counsel, and representatives of DTN:

                (a) access (in the presence of any representative  designated by
          WSC, at WSC's option),  upon  reasonable  prior notice,  during normal
          business hours, to all facilities,  property,  accounts, books, deeds,
          title papers,  insurance policies,  licenses,  agreements,  contracts,

                                       18
                                    - 329 -
<PAGE>

          commitments,   records,  equipment,  machinery,  fixtures,  furniture,
          vehicles,  accounts  payable and  receivable,  and  inventories of WSC
          (but, in any event,  not  personnel,  unless WSC  otherwise  consents)
          related to the WSC Business; and

                (b) all such  other  information  in WSC's  and its  Affiliates'
          possession  concerning the WSC Business as DTN may reasonably request,
          in each case at DTN's  expense;  provided that the foregoing  does not
          disrupt or interfere  with the business and  operations  of WSC in any
          material respect.

      6B.  Confidential   Information.   If  for  any  reason  the  transactions
contemplated in this Agreement are not consummated, WSC will not use or disclose
to any Person  (except  to its  agents,  representatives  and  advisors,  to its
lenders and security holders and their respective  agents,  representatives  and
advisors,  or as may  be  required  by  any  applicable  law)  any  confidential
information received from DTN or any of their respective agents, representatives
and advisors (each a "disclosing  party" for purposes of this Section 6B) in the
course  of   investigating,   negotiating,   and  completing  the   transactions
contemplated by this Agreement.

      6C.  Efforts to Consummate.  Subject to the provisions of this  Agreement,
WSC and ABRY will  each use  reasonable  efforts  to  fulfill  and  perform  all
conditions and  obligations on its part to be fulfilled and performed under this
Agreement  and to cause the  conditions  set forth in Articles VIII and IX to be
fulfilled and cause the Merger and the other  transactions  contemplated by this
Agreement in  connection  with the Merger to be fully  carried out. In addition,
promptly  after  WSC  (prior  to the  Commencement  Time) or ABRY  (prior to the
Closing)  becomes aware of any fact of circumstance  which  constitutes or would
constitute a breach of any  representation  or warranty of WSC, DTN, ABRY or the
Merger  Sub set  forth in this  Agreement,  WSC or ABRY  will  give  DTN  notice
thereof.

      6D. Non-Solicitation. From the date of this Agreement until the Closing or
the earlier  termination  of this  Agreement,  ABRY will not, and will not cause
(and  will  use  reasonable  efforts  not to  permit)  any of its  Subsidiaries,
Affiliates,  directors,  officers,  employees,  representatives  or  agents  to,
directly  or  indirectly  solicit,  or  initiate,  entertain  or enter  into any
discussions or  transactions  with, or encourage or provide any  information to,
any Person (other than any Person described in Section 6B),  concerning any sale
of  any of  the  assets  of WSC  or of  its  Affiliates  or  any  merger,  stock
acquisition or similar  transaction  involving WSC or its  Affiliates;  provided
that nothing in this Section 6D will prohibit ABRY from  furnishing,  or causing
or permitting  any other Person to furnish,  information  concerning  WSC or its
Affiliates to any governmental  authority or court of competent  jurisdiction or
any other Person as may be required by law.

      6E. Non-Competition. ABRY covenants and agrees, as an inducement to DTN to
enter  into this  Agreement  and to  consummate  the  transactions  contemplated
herein, that for a period of three years following the Closing Date neither ABRY
nor any  Affiliate  of ABRY (for so long but only for so long as it  remains  an
Affiliate of ABRY) will, directly or indirectly,  carry on or participate in the
ownership, management or control of, or license Intellectual Property to be used
in a manner  competitive with the WSC Business by, any business  enterprise that
competes anywhere in the world with the WSC Business as it is being conducted on
the Closing  Date;  provided  that this Section 6E will not prohibit ABRY or any

                                       19
                                    - 330 -
<PAGE>

Affiliate  of  ABRY  from  owning  less  than  10% of the  common  stock  of any
publicly-traded company or from owning any interest in, managing, controlling or
participating  in the  management or control of, or licensing  any  Intellectual
Property to, any business  enterprise that so competes but the primary  business
of which is not the WSC Business.

      6F.  Confidentiality.  After the Closing,  ABRY shall continue to maintain
the confidentiality of all information,  documents and materials relating to the
WSC Business which remain in ABRY's possession,  except to the extent disclosure
of any such  information  is (a) required by law, (b)  authorized  by DTN or (c)
reasonably  occurs in connection with disputes over, or arising under, the terms
of this Agreement. In the event that ABRY reasonably believes after consultation
with counsel that it is required by law to disclose any confidential information
described  in this  Section 6F,  ABRY will (a)  provide  DTN with prompt  notice
before  such  disclosure  in order that DTN may  attempt to obtain a  protective
order or other  assurance  that  confidential  treatment  will be accorded  such
confidential information and (b) cooperate with DTN in attempting to obtain such
order or  assurance.  The  provisions  of this Section 6F shall not apply to any
information,  documents or materials which are, as shown by appropriate  written
evidence,  in the public domain or, as shown by  appropriate  written  evidence,
shall come into the public domain, other than by ABRY or its Affiliates.


                                   ARTICLE VII

                       COVENANTS OF DTN AND THE MERGER SUB

      7A.  Confidential   Information.   If  for  any  reason  the  transactions
contemplated in this Agreement are not  consummated,  each of DTN and the Merger
Sub  will  not  use  or   disclose   to  any  Person   (except  to  its  agents,
representatives  and  advisors,  to its  lenders  and their  respective  agents,
representatives  and advisors,  or as may be required by any applicable law) any
confidential  information  received from WSC, any of its  Affiliates,  or any of
their respective agents, representatives and advisors (each a "disclosing party"
for  purposes of this Section 7A) in the course of  investigating,  negotiating,
and completing the transactions contemplated by this Agreement.

      7B.  Efforts to Consummate.  Subject to the provisions of this  Agreement,
each of DTN and the  Merger  Sub will use  reasonable  efforts  to  fulfill  and
perform all conditions and obligations on its part to be fulfilled and performed
under this  Agreement and to cause the conditions set forth in Articles VIII and
IX to be fulfilled  and cause the Merger and the  transactions  contemplated  by
this  Agreement  in  connection  with the  Merger to be fully  carried  out.  In
addition,  promptly  after DTN or the  Merger  Sub  becomes  aware  prior to the
Closing of any fact or  circumstance  which  constitutes  or would  constitute a
breach of any representation or warranty of DTN, the Merger Sub, WSC or ABRY set
forth in this Agreement, DTN will give ABRY notice thereof.

      7C.  Continued  Employment.  WSC or the Merger  Sub,  in its  capacity  as
Post-Merger  WSC after the  Effective  Time,  will pay to each  Person  who is a
common  law  employee  of WSC at the  Commencement  Time and to whom it does not
offer continued  employment  after the Closing Date at the same rate of base pay

                                       20
                                    - 331 -
<PAGE>

and the other terms and conditions  applicable to such  employment at such time,
severance  compensation  in the form of a payment  equal to one (1) week's  base
pay,  and DTN and the Merger Sub agree to  indemnify  and hold  harmless the WSC
Stockholders  and the  present and former  officers,  directors,  employees  and
agents  of each of the WSC  Stockholders  and  their  respective  Affiliates  in
respect of any loss,  liability,  cost,  damage,  claim or expense  which may be
incurred  by or asserted  against any of them  arising out of or relating to any
failure or refusal to so employ  any such  Person  (including  any change in any
term or condition of such  employment),  or the termination of the employment of
any such Person,  at or after the Closing Date.  Without  limiting the foregoing
indemnity,  it is  acknowledged  that such employees will continue to be at-will
employees, and the respective employers may terminate their employment or change
their  terms  of  employment  at  will,  and/or  WSC,  Post-Merger  WSC or their
respective  Affiliates  may cover such  employees  under existing or new benefit
plans, programs,  and arrangements,  and may amend or terminate the terms of any
such  plans,  programs,  or  arrangements  at any time (in  each  case,  without
reducing the  indemnity  obligation  set forth in the  preceding  sentence).  No
employee or beneficiary of WSC,  Post-Merger WSC or their respective  Affiliates
may sue to enforce  the terms of this  Agreement,  including  specifically  this
Section  7C, and no such  employee  or  beneficiary  shall be treated as a third
party beneficiary of this Agreement.


                                  ARTICLE VIII

                      CONDITIONS TO THE OBLIGATIONS OF WSC
                       AND WSC STOCKHOLDERS AT THE CLOSING

      The obligation of WSC and to the WSC Stockholders to consummate the Merger
is, at WSC's and the WSC Stockholders' option, subject to the fulfillment of the
following conditions at the time of the Closing:

      8A.  Representations, Warranties, Covenants.

          (1) Each of the  representations  and warranties of DTN and the Merger
      Sub set forth in Article V,  considered  without regard to any materiality
      qualifiers contained therein, will be deemed to be made again at and as of
      the time of the  Closing,  and taken as a whole such  representations  and
      warranties,  as so  remade,  will be true  and  accurate  in all  material
      respects,  except  to the  extent of  deviations  therefrom  permitted  or
      contemplated by this Agreement; and

          (2) each of DTN and the Merger Sub will in all material  respects have
      performed and complied with the covenants and agreements  required by this
      Agreement to be  performed or complied  with by it prior to or at the time
      of the  Closing,  taken as a whole  (other than the delivery of the Merger
      Consideration for the WSC Share Equivalents and the payments  described in
      Section 2D).

      8B.  Sufficient  Funds to  Satisfy  Obligations.  WSC will  have  received
evidence which is reasonably  satisfactory  to WSC to the effect that the Merger
Sub will have the funds described in Section 2D.

                                       21
                                    - 332 -
<PAGE>




      8C. DTN Legal  Opinion.  WSC and ABRY shall have  received an opinion from
Abrahams,  Kaslow,  & Cassman (or another firm reasonably  acceptable to WSC and
ABRY), counsel to DTN and the Merger Sub, dated the Closing Date,  substantially
in the form of the attached Exhibit 8C and otherwise reasonably  satisfactory to
WSC and ABRY.

      8D. Other. The Merger will have been approved by the requisite  members of
the board of directors and stockholders of the Merger Sub.

                                   ARTICLE IX

                    CONDITIONS TO THE OBLIGATIONS OF DTN AND
                          THE MERGER SUB AT THE CLOSING

      The obligations of the Merger Sub to pay the Merger  Consideration for the
WSC Share  Equivalents and consummate the Merger on the Closing Date are, at the
Merger Sub's option,  subject to the fulfillment of the following  conditions at
the time of the Closing:

      9A. Representations, Warranties, Covenants.

          (1) Each of the  representations  and  warranties  of WSC and ABRY set
      forth in Article  III  (other  than  Sections  3I or 3W) and  Article  IV,
      considered without regard to any materiality qualifiers contained therein,
      will be deemed to be made again at and as of the Commencement  Time (or at
      the time of the Closing, in the case of the representations and warranties
      set forth in Section  3B), and taken as a whole such  representations  and
      warranties,  as so remade, will be true and accurate, except to the extent
      of  deviations  therefrom  which are  permitted  or  contemplated  by this
      Agreement  or which,  in the  aggregate,  do not  constitute  and have not
      caused a Material Adverse Change;

          (2) WSC will in all material respects have performed and complied with
      the covenants and agreements required by this Agreement to be performed or
      complied with by it prior to or at the Closing, taken as a whole; and

          (3) ABRY will in all material  respects  have  performed  and complied
      with  the  covenants  and  agreements  required  by this  Agreement  to be
      performed  or complied  with by it prior to or at the time of the Closing,
      taken as a whole.

      9B. WSC Legal  Opinion.  DTN and the Merger  Sub shall  have  received  an
opinion from Lucash Gesmer & Updegrove (or another firm reasonably acceptable to
DTN),  counsel to WSC, dated the Closing Date,  substantially in the form of the
attached Exhibit 9B and otherwise reasonably satisfactory to DTN.

      9C.  ABRY  Legal  Opinion.  DTN and the  Merger  Sub shall  have  received
opinions from Testa, Hurwitz & Thibeault (or another firm reasonably  acceptable
to DTN),  counsel to ABRY, dated the Closing Date,  substantially in the form of
the attached  Exhibit 9C and  otherwise  reasonably  satisfactory  to DTN,  with
customary qualifications,  exceptions and assumptions reasonably satisfactory to
DTN.

                                       22
                                    - 333 -
<PAGE>




      9D. Other. The Merger will have been approved by the requisite  members of
the board of directors and the WSC Stockholders.


                                    ARTICLE X

                              PRECLOSING COVENANTS

      10A. Public Announcements. WSC, ABRY and DTN shall consult with each other
before issuing any press releases or otherwise making any public statements with
respect to the  Merger  and shall not issue any such  press  release or make any
such public statement prior to such  consultation,  except as may be required by
law.

      10B.  WSC  Stockholder   Meeting.   WSC  will  serve  notice  to  all  WSC
Stockholders  of a  shareholder  meeting  to be  held  in  connection  with  the
transactions  contemplated  herein  at least  20 days  prior to the date of such
meeting and hold such  meeting in  accordance  with the  Massachusetts  Business
Corporation  Law.  Such  notice  will  contain  a  statement  of the  rights  of
dissenting  shareholders  in  accordance  with  Section 87 of the  Massachusetts
Business Corporation Law. WSC shall notify DTN of the results of the meeting.

      10C. Management and Consulting Agreement.

          (1) Engagement. WSC, ABRY and DTN agree as follows:

                (a) As of the close of  business  on the date of this  Agreement
          (the  "Commencement  Time"),  WSC hereby engages DTN as manager of the
          WSC  Business  and as  consultant  thereto and DTN will  provide  such
          management  and consulting  services to WSC as DTN deems  necessary or
          appropriate  for the  purpose of  operating  the WSC  Business  in the
          ordinary course until the Closing.  As of the  Commencement  Time, DTN
          shall have all  authority  required  to direct the  operations  of WSC
          Business in the ordinary course,  including the authority to cause WSC
          to obtain funds  available to WSC under the Bank Loan  Agreement to be
          used for the purpose of managing  the ordinary  operations  of the WSC
          Business;  and WSC will use its best efforts to cause its employees to
          act in  accordance  with DTN's  instructions  given  pursuant  to such
          authority.

                (b) DTN will perform  management and  consulting  services under
          this Section 10C as an independent contractor,  retaining control over
          and responsibility  for its own operations and personnel.  Neither DTN
          nor its officers,  employees or agents will be considered employees or
          agents  of WSC,  ABRY or any of their  Affiliates  as a result of this
          Section  10C,  nor will any of them have  authority to contract in the
          name of or bind WSC by reason of this Section 10C, or to terminate any
          employee of WSC, except as WSC may expressly agree in writing.

                                       23
                                    - 334 -
<PAGE>




                (c) DTN shall not be paid any fees or  remuneration by WSC, ABRY
          or any of their  Affiliates  for providing  management  and consulting
          services pursuant to this Section 10C.

          (2) Liability.  Neither DTN nor any of its  Affiliates,  stockholders,
      officers,  employees or agents will be liable to WSC, ABRY or any of their
      Affiliates  for  Damages   arising  out  of  or  in  connection  with  the
      performance  of services  contemplated  by this Section  10C,  unless such
      Damages are a result of the gross negligence or willful misconduct of such
      Person; provided that if, prior to the termination of this Agreement, each
      of the  conditions  to the  obligations  of DTN and the  Merger Sub at the
      Closing  under  Article IX is  satisfied  or waived and the  Agreement  is
      nonetheless  terminated  by DTN,  DTN will  reimburse  WSC for all amounts
      borrowed  under  the Bank Loan  Agreement  after  the  Commencement  Time,
      together  with  interest  thereon  at the rate  provided  in the Bank Loan
      Agreement,  to the  extent  not  paid  or  repaid  by WSC  prior  to  such
      termination.  Prior to the Closing Date,  DTN will not cause WSC to borrow
      any funds in connection with the  performance of services  contemplated by
      this Section 10C other than under the Bank Loan Agreement.

          (3) No Breach.  Notwithstanding any provision to this Agreement,  none
      of the  following (i) will be deemed to constitute a breach by WSC or ABRY
      of any representation,  warranty,  covenant or agreement set forth in this
      Agreement or (ii) will give rise to any claim for  indemnification by ABRY
      pursuant to Section 12F of this Agreement:

                (a) any fact or circumstance  which occurs primarily as a result
          of any action or omission to act of DTN;

                (b) any  action  taken or  omission  to act by WSC or any of its
          employees,  officers or directors in compliance  with any direction by
          DTN or any representative thereof; or

                (c) any fact or circumstance  which occurs primarily as a result
          of any item described in clause 10C(3)(b) above.

In addition,  an opinion of legal counsel to WSC which is  substantially  in the
form of the  attached  Exhibit  9B,  except  only in  those  respects  that  are
consequences  of  items  described  in  clauses  (a),  (b) and (c)  above,  will
nonetheless  be  deemed to  satisfy  the  condition  set  forth in  Section  9B.
Notwithstanding  anything in this Section  10C, DTN will not have the  authority
prior to the Closing to take or direct WSC or any of its employees,  officers or
directors to take any action on WSC's behalf with respect to this  Agreement (as
distinct from actions relating to the conduct of the WSC Business).


                                       24
                                    - 335 -
<PAGE>




                                   ARTICLE XI

                                   TERMINATION

      11A.  Termination.  This  Agreement may be terminated at any time prior to
the Closing only as follows:

          (1) by the mutual written consent of DTN and WSC;

          (2) by WSC,  if there  has  been a  material  breach  by DTN or by the
      Merger Sub of any material covenant,  representation or warranty contained
      in this Agreement which has prevented the satisfaction of any condition to
      the  obligations of WSC at the Closing and such breach has not been waived
      by WSC or, in the case of a covenant breach, cured by DTN or by the Merger
      Sub, as the case may be, on or prior to the  earlier of December  11, 1998
      or the tenth (10th) day after written notice thereof from WSC;

          (3) by DTN,  if there has been a material  breach by WSC or by ABRY of
      any  material  covenant,  representation  or  warranty  contained  in this
      Agreement  which has  prevented the  satisfaction  of any condition to the
      obligations of DTN or of the Merger Sub at the Closing and such breach has
      not been  waived by DTN or the  Merger  Sub or, in the case of a  covenant
      breach, cured by WSC on or prior to December 11, 1998, or the tenth (10th)
      day after written notice thereof from DTN;

          (4) by either WSC or DTN if the transactions  contemplated hereby have
      not been consummated by December 11, 1998; or

          (5) by DTN, if the WSC Stockholders have not approved the transactions
      contemplated  hereby as required pursuant to the applicable  provisions of
      the  Massachusetts  Business  Corporation  Law on or prior to December 11,
      1998;  provided,  however,  that  neither WSC nor DTN shall be entitled to
      terminate  this  Agreement  pursuant to this Section 11A if such  Person's
      breach  of  this   Agreement  has  prevented  the   consummation   of  the
      transactions contemplated hereby.

      11B.  Effect of  Termination.  In the event that this  Agreement  shall be
terminated  pursuant  to Section  11A,  all further  obligations  of the parties
hereto  under this  Agreement  or  otherwise  shall  terminate  without  further
liability or obligation of WSC, ABRY, DTN or the Merger Sub; provided,  however,
that no party shall be released from  liability  hereunder if this  Agreement is
terminated  pursuant  to Section  11A by reason of such  party's  breach of this
Agreement,  and Sections 7A and 10C(2)  shall  survive any  termination  of this
Agreement.

      11C.  Waiver  of Right to  Terminate.  WSC and DTN shall be deemed to have
waived their  respective  rights to terminate this Agreement upon the completion
of the  Closing.  No such waiver  shall  constitute a waiver of any other rights
arising from the non-fulfillment of any condition precedent set forth in Article
VIII or IX hereof or any  misrepresentation or breach of any warranty,  covenant
or agreement contained herein unless such waiver is made in writing and then any
such written waiver shall only  constitute a waiver of the specific  matters set
forth therein.

                                       25
                                    - 336 -
<PAGE>





                                   ARTICLE XII

                 ADDITIONAL AGREEMENTS; COVENANTS AFTER CLOSING

      12A.  Survival of  Representations  and Warranties.  The  representations,
warranties, covenants and agreements of WSC and ABRY set forth in this Agreement
or in any writing  delivered to DTN or to the Merger Sub in connection with this
Agreement shall survive the Closing to the extent provided in Section 12F.

      12B.  Mutual  Assistance and Records.  Each of DTN and WSC agree that they
will mutually  cooperate in the expeditious  filing of all notices,  reports and
other filings with any governmental  authority  required to be submitted jointly
by DTN and WSC in connection  with the execution and delivery of this Agreement,
the  other   agreements   contemplated   hereby  and  the  consummation  of  the
transactions contemplated hereby or thereby. Subsequent to the Closing, ABRY and
DTN,  at their own cost,  will  assist  each  other  (including  making  records
available) in the preparation of their respective Tax Returns and the filing and
execution of any Tax elections, if required, as well as any audits or litigation
that may  ensue as a result  of the  filing  thereof,  to the  extent  that such
assistance is reasonably requested.

      12C. Access.  DTN and WSC agree that after the Commencement Time WSC shall
provide ABRY with reasonable access to any books, records, correspondence, files
and other information retained by WSC hereunder, at ABRY's expense.

      12D.  Expenses.  DTN,  WSC and ABRY  will  pay all of  their  own fees and
expenses  in  connection  with  the  Agreement  and  the   consummation  of  the
transactions contemplated hereby.

      12E.  Taxes;   Recording  Charges.   All  sales,  use,  transfer,   stamp,
conveyance, value added or other Taxes arising out of the Merger or otherwise on
account of this Agreement or the consummation of the  transactions  contemplated
hereby and all charges for or in  connection  with the recording of any document
or instrument contemplated hereby shall be paid by the Merger Sub.

      12F. Indemnification by ABRY.

          (1) After Closing and subject to the terms and conditions set forth in
      this  Agreement,   ABRY  will  indemnify  DTN  and  Post-Merger  WSC  (the
      "Indemnified Parties") against, and agrees to hold them harmless from, any
      and all Damages  incurred  or  suffered by any of them,  arising out of or
      related  in  any  way  to  (i)  any  misrepresentation  or  breach  of any
      representation,  warranty  or  covenant  of WSC or ABRY set  forth in this
      Agreement,  or the operation of the WSC Business prior to the Commencement
      Time,  (ii) any  amount  owed by WSC to Peter R.  Leavitt  or  Michael  S.
      Leavitt, or claimed by them from WSC, or any other claim asserted by Peter
      R. Leavitt or Michael S. Leavitt against DTN or Post-Merger WSC,  existing
      or arising out of,  facts or  circumstances  existing at, or prior to, the
      Closing  in excess of the  $144,397  described  in Section  2D,  (iii) any
      Damages  related to or in  connection  with the  exercise of rights  under
      Sections 86 to 98 of the Massachusetts Business Corporation Law by any WSC
      Stockholder  who  dissents  from a vote  to  consummate  the  transactions

                                       26
                                    - 337 -
<PAGE>

      contemplated  herein,  or any  liability  of DTN or  Post-Merger  WSC as a
      result of the  exercise of such  rights or  remedies  and (iv) any Damages
      arising  from or related  to any claim by John C.  Keelan  against  WSC as
      described in that certain demand letter, dated July 2, 1998; provided that
      ABRY's  liability  pursuant  to this  Section  12F will be  subject to the
      following limitations:

                (a) ABRY will not be liable for any Damages  described in clause
          (1)(i) above unless and until the aggregate amount of all such Damages
          exceeds $50,000 (the "Threshold Amount"),  in which event ABRY will be
          liable  for such  Damages  to the extent  that such  aggregate  amount
          exceeds the Threshold Amount.  The Threshold Amount shall not apply to
          (i) any Taxes related to or in connection  with the conduct of the WSC
          Business up to the Commencement Time  ("Pre-Commencement  Taxes"),  or
          (ii) any breach of any representation or warranty set forth in Section
          3I or 3W of this  Agreement.  ABRY will not be liable for any  Damages
          described  in  clause  (1)(i)  above  relating  to any  breach  of any
          representation  or warranty set forth in Section 3I of this  Agreement
          unless  and until the  aggregate  amount of all such  Damages  exceeds
          $60,000 (the "Receivables Threshold Amount"), in which event ABRY will
          be liable for such Damages to the extent such aggregate amount exceeds
          the Receivables Threshold Amount.

                (b) ABRY will not be liable  for any  Damages  (other  than Pre-
          Commencement  Taxes) described in clause (1)(i) above unless DTN gives
          ABRY written notice asserting the  misrepresentation,  breach or other
          matter in question prior to the first anniversary of the Closing Date.

                (c)  ABRY  will  not be  liable  for  any  Damages  (other  than
          Pre-Commencement Taxes) described in clause (1)(i) above to the extent
          that the aggregate amount of all Damages (other than  Pre-Commencement
          Taxes) described in clause (1)(i) above exceeds the sum of $500,000.

In the case of any claim described in clause (1)(i), (ii), (iii) and (iv) above,
Damages will include  compensation  for the business time spent by DTN employees
to testify or be deposed as may be required by judicial  process or requested by
ABRY in any  proceeding  brought by a third party and business time spent in any
related  travel (such  business time to be reimbursed at a rate equal to one and
one-half  times the rate of base pay of the employee in question) and reasonable
out-of-pocket  expenses  incurred in connection  with such  required  testimony,
deposition or travel.

          (2) Notice of Claims.  If any Person  believes  that it will suffer or
      has  suffered,  or will incur or has  incurred,  any Damages as to which a
      remedy may be had by it pursuant to this  Section  12F,  such Person shall
      notify  ABRY  promptly  in writing  describing  such  Damages,  the amount
      thereof, if known, and the method of computation of such Damages, all with
      reasonable particularity.

          (3) Defense of Third Party Claims. ABRY will have the right to conduct
      and control  through  counsel of its own choosing any related  third party
      claim,  action, or suit, but DTN or Post-Merger WSC may at their election,

                                       27
                                    - 338 -
<PAGE>

      participate in the defense of any such claim, action, or suit at their own
      cost and expense;  provided  that, if ABRY fails to defend any such claim,
      action, or suit, then DTN or Post-Merger WSC may

                (a) defend such claim, action or suit through counsel of its own
          choosing such claim, action, or suit,

                (b) so long as it gives  ABRY at least  fifteen  (15) days prior
          written  notice of the terms of the  proposed  settlement  thereof and
          permits ABRY to then undertake the defense thereof, settle such claim,
          action or suit, and

                (c) recover  from ABRY the amount of such  settlement  or of any
          judgment and the costs and expenses of such defense.

      ABRY will not compromise or settle any such third party claim,  action, or
      suit  unless (1) as a result of such  compromise  or  settlement,  DTN and
      Post-Merger WSC will be released from all liability to such third party or
      (2) ABRY obtains the prior written  consent of DTN and  Post-Merger WSC to
      such  compromise or  settlement,  which  consent will not be  unreasonably
      withheld or delayed.

          (4)  Assignment  of Rights  Against  Peter R.  Leavitt  and Michael S.
      Leavitt.  At or after the Closing,  DTN and Post-Merger WSC will take such
      actions as may be required,  at ABRY's election,  either to assign to ABRY
      or otherwise  permit ABRY to have,  the right to pursue all remedies  that
      WSC may have against  Peter R.  Leavitt or Michael S. Leavitt  existing or
      arising  out of any  fact or  circumstance  existing  at or  prior  to the
      Closing  (including any claim for any breach of representation or warranty
      or fraud in connection with  transactions  consummated on or about January
      22, 1997),  and (if such  assignment  has not occurred) ABRY will have the
      right to commence, conduct and control through counsel of its own choosing
      any claim, action or suit in connection with the pursuit of such remedies.
      Any such assignment or other action by DTN and/or  Post-Merger WSC will be
      at ABRY's  request  and  expense  at or any time  after  Closing.  Without
      limiting the foregoing,  DTN and  Post-Merger  WSC agree that ABRY will be
      entitled  to exercise  such rights or pursue such  remedies in the name of
      DTN and/or  Post-Merger WSC and that ABRY will be entitled to all proceeds
      resulting from any such remedy,  less any reasonable  expenses  (including
      any Tax) incurred by DTN or Post-Merger WSC in connection with the pursuit
      of such remedies (which expenses will be reimbursed by ABRY in any event).

                                  ARTICLE XIII

                                  MISCELLANEOUS

      13A.  Amendment  and  Waiver.  This  Agreement  may be  amended,  and  any
provision of this  Agreement may be waived,  only if such amendment or waiver is
set forth in a writing  executed  by WSC,  DTN and  ABRY.  No course of  dealing
between or among any  persons  having any  interest  in this  Agreement  will be
deemed effective to modify, amend or discharge any part of this Agreement or any
rights or  obligations  of any person under or by reason of this  Agreement.  No

                                       28
                                    - 339 -
<PAGE>

waiver  of any of the  provisions  of this  Agreement  shall be  deemed or shall
constitute, a waiver of any other provisions,  whether or not similar, nor shall
any waiver  constitute a continuing  waiver.  The remedies  provided  herein are
cumulative and not exclusive of any remedies available at law or in equity.

      13B. Notices. All notices, demands and other communications to be given or
delivered  to DTN,  the  Merger  Sub,  WSC or ABRY  under  or by  reason  of the
provisions of this  Agreement will be in writing and will be deemed to have been
given when personally delivered,  sent by reputable overnight courier, or mailed
by first class mail,  return receipt  requested,  to the address indicated below
(unless another address is so specified in writing):

      Notices to WSC:
      ---------------

      Weather Services Corporation
      c/o ABRY Partners, Inc.
      18 Newbury Street
      Boston, Massachusetts 02116
      Attention: P. Koenig

      With a copy (which will not constitute notice) to each of:

      Lucash Gesmer & Updegrove
      40 Broad Street
      Boston, MA 02109-4310
      Attention: William Contente, Esq.

      Notices to ABRY:
      ----------------

      c/o ABRY Partners, Inc.
      18 Newbury Street
      Boston, MA  02116
      Attention:  P. Koenig

      with a copy (which will not constitute notice) to:

      Kirkland & Ellis
      Citicorp Center
      153 East 53rd Street
      New York, New York 10022-4675
      Attention: J. Kuehn, Esq.

      Notices to DTN, the Merger Sub or Post-Merger WSC:
      --------------------------------------------------

      Data Transmission Network Corporation
      9110 West Dodge Road, Suite 200
      Omaha, Nebraska 68114
      Attention: G.T. Sloma

                                       29
                                    - 340 -
<PAGE>




      with a copy (which will not constitute notice) to:

      Abrahams, Kaslow & Cassman
      8712 West Dodge Road
      Suite 300
      Omaha, NE         68114-3419
      Attention:        M.M. Lofgren, Esq.

      13C. Assignment.  This Agreement and all of the provisions hereof shall be
binding upon and inure to the benefit of the parties hereto and their respective
successors  and assigns.  Neither  this  Agreement  nor any rights,  benefits or
obligations  set forth  herein may be assigned by WSC, DTN or  Post-Merger  WSC,
except that DTN or  Post-Merger  WSC may assign its rights under this  Agreement
and any of the  provisions  hereof,  as  collateral  security to any lender,  in
connection with the sale of the business or assets of Post-Merger WSC, or to any
Affiliate of DTN.

      13D.  Severability.  Whenever  possible,  each provision of this Agreement
will be interpreted in such manner as to be effective and valid under applicable
law, but if any  provision  of this  Agreement  is held to be  prohibited  by or
invalid under  applicable  law, such provision  will be ineffective  only to the
extent of such prohibition or invalidity,  without invalidating the remainder of
such provision or the remaining provisions of this Agreement.

      13E. No Strict Construction.  The language used in this Agreement shall be
deemed to be the language  chosen by the parties  hereto to express their mutual
intent, and no rule of strict construction will be applied against any Person.

      13F. Captions.  The captions used in this Agreement are for convenience of
reference  only and do not  constitute a part of this Agreement and shall not be
deemed  to  limit,  characterize  or in any way  affect  any  provision  of this
Agreement,  and all provisions of this Agreement shall be enforced and construed
as if no caption had been used in this Agreement.

      13G.  Third Parties.  Nothing  herein  expressed or implied is intended or
shall be  construed to confer upon or give to any person,  firm or  corporation,
other than the parties  hereto and their  respective  permitted  successors  and
assigns, any rights or remedies under or by reason of this Agreement, such third
parties  specifically  including but without  limitation any investors of DTN or
WSC or employees of WSC.

      13H.  Complete  Agreement.  This  document and the  documents  referred to
herein  contain the complete  agreement  between the parties and  supersede  any
prior  understandings,  agreements or representations by or between the parties,
written or oral, which may have related to the subject matter hereof in any way.

      13I.  Counterparts.  This  Agreement  may  be  executed  in  one  or  more
counterparts,  all of which taken  together  shall  constitute  one and the same
instrument.


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<PAGE>




      13J. Governing Law. The internal law, but not the law of conflicts, of the
Commonwealth  of  Massachusetts   will  govern  all  questions   concerning  the
construction,  validity and interpretation of this Agreement and the performance
of the obligations imposed by this Agreement.

      13K. Specific Performance. Each of WSC and ABRY recognizes and agrees that
a breach by it of any of its covenants and  agreements in this  Agreement  could
cause  irreparable  harm to DTN, that DTN's remedies at law in the event of such
breach would be inadequate, and that, accordingly, in the event of such breach a
restraining  order or  injunction  or both may be issued  against the  breaching
Person in addition to any other rights and remedies that may be available to DTN
under  applicable  law.  If the  agreement  set  forth  in  Section  6E is  more
restrictive  than permitted by the applicable laws of the  jurisdiction in which
DTN or the Merger Sub seeks enforcement thereof,  Section 6E shall be limited to
the extent required to permit enforcement under such applicable laws.

                                    * * * * *

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                                    - 342 -
<PAGE>




      IN WITNESS WHEREOF,  the parties hereto have executed this Agreement as of
the date first written above.


                          WSC:
                          ----

                          WEATHER SERVICES CORPORATION


                          By:/s/ Robert MacInnis

                          Its:Treasurer


                          DTN:
                          ----

                          DATA TRANSMISSION NETWORK CORPORATION


                          By:/s/ Joseph M. Urzendowski

                          Its: Vice President Operations


                          ABRY:
                          -----

                          ABRY BROADCAST PARTNERS II, L.P.
                          By ABRY Capital, L.P.
                          Its General Partner

                          By: ABRY Holdings, Inc.
                          Its General Partner

                          By:/s/ Peggy Koenig

                          Its:






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                                    - 343 -
<PAGE>




                                    APPENDIX

      "ABRY" shall have the meaning set forth in the  introductory  paragraph of
this Agreement.

      "Accounts Receivable" shall have the meaning set forth in Section 3I.

      "Affiliate"  of any Person means any other Person which is controlled  by,
controls, or is under common control with, such first Person.

      "Agreement" shall have the meaning set forth in the introductory paragraph
of this Agreement.

      "Bank Loan  Agreement"  shall have the meaning set forth in the definition
of the term "Loan Agreements."

      "Benefit Plan" shall have the meaning set forth in Section 3S(i).

      "Closing" shall have the meaning set forth in Section 2C.

      "Closing Date" shall have the meaning set forth in Section 3C.

      "Code" shall have the meaning set forth in Section 3M.

      "Commencement Time" shall have the meaning set forth in Section 10C(1).

      "Damages"  shall mean all  demands,  claims,  actions or causes of action,
assessments,  losses, damages, costs, expenses, liabilities,  judgments, awards,
fines, sanctions, penalties, charges and amounts paid in settlement,  including,
without limitation,  reasonable costs, fees and expenses of attorneys,  experts,
accountants,  appraisers,  consultants,  witnesses,  investigators and any other
gents or  representatives of such Person (with such amounts to be determined net
of any resulting Tax benefit actually received or realized and net of any refund
or reimbursement  of any portion of such amounts actually  received or realized,
including, without limitation,  reimbursement by way of insurance or third party
indemnification), but specifically excluding (i) except as otherwise provided in
this Agreement,  any costs incurred by or allocated to Indemnified  Parties with
respect  to time spent by  employees  of the  Indemnified  Parties or any of its
Affiliates  and (ii) any lost  profits  or  opportunity  costs or  exemplary  or
punitive damages (except to the extent assessed in connection with a third-party
claim with respect to which the Person  against  which such damages are assessed
is entitled to indemnification hereunder).

      "DTN" shall have the meaning set forth in the  introductory  paragraph  of
this Agreement.

      "DTN Warrant" shall have the meaning set forth in Section 2A.


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                                    - 344 -
<PAGE>




      "Effective  Time"  means the time of the filing of the  Articles of Merger
described in Section 1C.

      "Environmental and Safety  Requirements"  means all federal,  state, local
and foreign  statutes,  regulations,  ordinances and other provisions having the
force  or  effect  of  law,   all  judicial   and   administrative   orders  and
determinations,  all  contractual  obligations  and all common law, in each case
concerning  public health and safety,  worker health and safety and pollution or
protection of the environment (including, without limitation, all those relating
to the presence, use, production,  generation,  handling, transport,  treatment,
storage,  disposal,  distribution,  labeling,  testing,  process ing, discharge,
release,  threatened  release,  control or cleanup of any hazardous or otherwise
regulated  materials,  substances  or wastes,  chemical  substances or mixtures,
pesticides,  pollutants,  contaminants,  toxic chemicals,  petroleum products or
byproducts, asbestos, polychlorinated biphenyls, noise or radiation).

      "ERISA" shall have the meaning set forth in Section 3S(i).

      "GAAP" shall have the meaning set forth in Section 3H.

      "Intellectual Property Rights" means all (i) patents, patent applications,
patent disclosures and inventions, (ii) trademarks,  service marks, trade dress,
trade names,  logos and corporate names and  registrations  and applications for
registration  thereof  together with all of the goodwill  associated  therewith,
(iii)  copyrights  (registered  or  unregistered)  and  copyrightable  works and
registrations  and applications for  registration  thereof,  (iv) mask works and
registrations and applications for registration  thereof, (v) computer software,
data,  data  bases and  documentation  thereof,  (vi)  trade  secrets  and other
confidential  information  (including,   without  limitation,  ideas,  formulas,
compositions,  inventions (whether patentable or unpatentable and whether or not
reduced to  practice),  know-how,  manufacturing  and  production  processes and
techniques,  research and  development  information,  drawings,  specifications,
designs,  plans, proposals,  technical data,  copyrightable works, financial and
marketing  plans and customer and supplier lists and  information),  (vii) other
intellectual  property rights and (viii) copies and tangible embodiments thereof
(in whatever form or medium).

      "Indemnified Parties" shall have the meaning set forth in 12F(1).

      "Intellectual  Property" shall mean all United States and foreign patents,
patent applications,  registered and unregistered Marks (as hereinafter defined)
and all  applications  for  registration  thereof,  registered and  unregistered
copyrights and all applications for registration thereof, industrial designs and
industrial  design  applications,   computer  software  programs,   data  bases,
inventions, trade secrets,  proprietary know-how, invention disclosures,  ideas,
formulae,  ingredient  compositions,   recipes,   manufacturing  and  production
processes and techniques,  technical  data,  standards,  specifications,  plans,
proposals,  financial business and marketing plans,  customer and supplier lists
and proprietary information of any type, whether or not written.



                                       34
                                    - 345 -
<PAGE>




      "Latest Balance Sheet" shall have the meaning set forth in Section 3H(ii).

      "Lien"  means  any  mortgage,  pledge,  hypothecation,  encumbrance,  lien
(statutory or otherwise),  preference,  priority or other security  agreement of
any kind or nature  whatsoever  (includ ing any conditional  sale or other title
retention agreement and any lease having substantially the same effect as any of
the  foregoing  and any  assignment  or deposit  arrangement  in the nature of a
security device).

      "Loan Agreements" shall mean (i) the Credit Agreement by and among WSC and
BankBoston,  N.A.,  dated as of August 8,  1997,  as  amended  (the  "Bank  Loan
Agreement"),  and the Master Lease Agreement and Master Lease Finance  Agreement
by and among WSC and  BankBoston  Leasing,  Inc.,  dated as of July 22, 1997, as
amended,  (ii)  the  Convertible  Promissory  Notes  issued  by WSC to  ABRY  on
September 29, 1997,  October 30, 1997,  November 26, 1997,  October 15, 1998 but
effective as of January 14, 1998 and on October 15, but  effective as of January
29,  1998,  (iii) the Credit  Agreement  by and among WSC and ABRY,  dated as of
October 15, 1998 but effective as of January 29, 1998,  and (iv) the  Promissory
Note,  dated as of August 13, 1997,  issued by WSC to Elizabeth  Ann Wallace and
David A.  Wallace,  trustees of the John E. Wallace  Non-Exempt  Marital  Trust,
dated October 19, 1972.

      "Management  Agreement" shall mean the Management and Consulting  Services
Agreement dated as of January 22, 1997 between ABRY Partners, Inc. and WSC.

      "Material  Adverse  Effect"  shall mean a material  adverse  effect on the
general business  affairs,  financial  condition or results of operations of the
WSC Business other than as a result of seasonal variations.

      "Merger" shall have the meaning set forth in Section 1B.

      "Merger Consideration" shall have the meaning set forth in Section 2A(1).

      "Merger Sub" shall have the meaning set forth in

      "Old WSC Certificates" shall have the meaning set forth in Section 1H.

      "Permitted  Encumbrance"  means (i) Liens  arising by operation of law and
securing  the  payment  of Taxes  which are not yet due and  payable,  (ii) with
respect  to any  property  leased by WSC,  the  interest  of the  lessor in such
property and (iii) easements, rights-of-way,  reservations of rights, conditions
or covenants,  zoning,  building or similar  restrictions or other  non-monetary
Liens or  defects  that do not,  individually  or in the  aggregate,  materially
interfere with the WSC Business as presently conducted.

      A "Person" means any individual,  partnership,  limited liability company,
joint venture,  corporation,  trust, unincorporated association or government or
department thereof.

      "Pre-Commencement  Taxes"  shall  have the  meaning  set forth in  Section
12F(1)(a).


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                                    - 346 -
<PAGE>




      "Post-Merger WSC" shall have the meaning set forth in Section 1B.

      "Receivables Threshold Amount" shall have the meaning set forth in Section
12F(1)(a).

      "Required  Intellectual  Property"  shall  have the  meaning  set forth in
Section 3O(i).

      With  respect  to  any  Person,  a  "Subsidiary"  means  any  corporation,
partnership,  limited liability company, association or other business entity of
which,  at the time of such reference,  (i) if a corporation,  a majority of the
total voting power of shares of stock entitled (without regard to the occurrence
of any  contingency) to vote in the election of directors,  managers or trustees
thereof,  or a majority economic  interest,  is at the time owned or controlled,
directly or indirectly,  by that Person or one or more of the other Subsidiaries
of that  Person or a  combination  thereof,  or (ii) if a  partnership,  limited
liability  company,  association  or other  business  entity,  a majority of the
partnership or other similar ownership  interest thereof is at the time owned or
controlled, directly or indirectly, by any Person or one or more Subsidiaries of
that Person or a combination  thereof.  For purposes hereof, a Person or Persons
will be deemed to have a majority ownership  interest in a partnership,  limited
liability  company,  association  or other  business  entity  if such  Person or
Persons will be allocated a majority of  partnership,  company,  association  or
other  business  entity  gains or  losses  or will be or  control  the  managing
director or general partner of such partnership,  company,  association or other
business entity.

      "Taxes" means all Taxes,  assessments,  charges,  duties,  fees, levies or
other governmental charges,  including,  without limitation,  all Federal, state
provincial,   local,   foreign  and  other  income,   capital  (including  large
corporations),  franchise,  profits,  capital gains,  capital  stock,  transfer,
sales,  use,  goods and services and other  value-added,  occupation,  property,
excise,  severance,  windfall profits,  stamp,  license,  payroll,  withholding,
estimated and other Taxes of any kind whatsoever, and deficiency assessments, as
well as all additions to Tax, penalties and interest imposed with respect to the
foregoing.

      "Tax Return" shall mean any return, declaration, report, claim for refund,
information  return or other  document  (including  any  related  or  supporting
schedule,  statement or information) filed or required to be filed in connection
with the determination,  assessment or collection of any Tax of any party or the
administration of any laws, regulations or administrative  requirements relating
to any Tax.

      "Threshold Amount" shall have the meaning set forth in 12F.

      "WSC  Business"  shall  have the  meaning  set  forth in the  introductory
paragraph of this Agreement.

      "WSC Closing  Documents" means all agreements,  certificates,  instruments
and other  documents  required by this Agreement to be executed and delivered by
WSC or the WSC Stockholders, as the case may be, at or before the Closing.


                                       36
                                    - 347 -
<PAGE>



      "WSC Right"  means any  security or right issued by WSC which is not a WSC
Share, which is outstanding immediately prior to the Effective Time and which is
directly or indirectly  convertible  into or exercisable or exchangeable for any
capital stock of WSC at such time.

      "WSC Share Equivalent" means any WSC Right or WSC Share.

      "WSC Share" means any share of capital  stock of WSC which is  outstanding
immediately prior to the Effective Time.

      "WSC Stockholders" means any Person who owns beneficially or of record WSC
Rights or WSC Shares.

                                       37
                                    - 348 -