From: capskb@alliant.backbone.uoknor.edu (Keith Brewster)
Subject: Re: Tornadoes in Florida?
Originator: news@essex.ecn.uoknor.edu
Date: Tue, 6 Oct 1992 21:38:37 GMT
Organization: University of Oklahoma, Norman, OK

In article <harris.718342636@drvax3> harris@drvax3.msfc.nasa.gov (Mitch Harris) writes:
>Does anyone have any info on the series of tornadoes that just hit
>Florida? Thnaks!
>
The following is a response I posted on WX-TALK mail group.
I thought it was of interest here, also. Those who have read it already
may press "n" now.

The post contains excerpts from a story in the St. Petersburg Times, which
is not duplicated in full in this forum.  The excerpts are selected based
on my thoughts, positive or negative; I don't intend to select parts
which show only one side of the story.

"(Rob Cermak)" <cermak@GANDALF.RUTGERS.EDU> quotes...
David K. Rogers
St. Petersburg Times Staff Writer

[stuff deleted]
>	* Despite these kinds of clues, weather service procedures restrict
>government meteorologists from issuing warnings until a tornado actually has
>touched down.
>
   This is not precisely true.  If you have clear evidence that a tornado
   is imminent (such as a spotter report of a strongly rotating wall cloud
   or a funnel), a warning is justified.  In this case the visibilty was
   very poor (St. Petersburg obs ranged from 3/4 to 2 miles) due to very
   high relative humidity (75 degrees with a 73 dew point).  The tower
   did not see the tornado until it was within a mile.

>	Issuing a tornado watch, a lesser designation meaning that tornadoes
>/could/ form, is even harder.  Federal meteorologists can't issue them unless
>conditions in Florida meet criteria for tornado formation in Kansas,
>Oklahoma and other Midwestern states.
>
   This is incorrect.  The forecasters at the Severe Storms Forecast Center
   (aka SELS) are fully aware of the various conditions (not all of which
   are typical of the Midwest) which can lead to tornado formation.
   In this case they had issued a slight risk based on the strong turning
   of the wind with height in the Tampa (Ruskin) sounding from 6am EDT
   Saturday. To quote:

ACUS1 KMKC 031420  
MKC AC 031500  
  
CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O  
  
VALID 031500 - 041200Z  
  
THERE IS A [slight] RISK OF [severe thunderstorms to the right of
a line from] 60 NW TPA [Tampa] to DAB [Daytona Beach].

[stuff deleted..."translated" text follows]

Although air mass is currently only marginally unstable [temps in 70's]
strength of wind fields and resultant hodgraphs [wind change as
a function of height in the sounding] suggest caution sould be
used while monitoring these [bands of convection approaching Tampa]
storms.
  
..ANTHONY.. 10/03/92  
[...end quote..]

  This situation is common in the right-front quadrant (relative to 
  movement) of hurricanes.  See article by McCaul, Monthly Weather
  Review, August, 1991, 1954-1978.  He shows that tornadoes in hurricanes
  can form with fairly low instability (relative to Midwestern tornado
  situations).  There was not a hurricane in this situation, but there 
  was a fairly strong tropical low, and the wind profiles were ripe.

  There will be a lot of questions about whether a tornado watch was
  warranted. That would have heightened the awareness of the
  cummunity.

  It is easy to pick out the simularities to a hurricane in retrospect, 
  so I hesitate to be critical of SELS, they had to make the decision in
  real-time.  I am left wondering why they didn't issue after the first
  report if they started out advising "caution" and seemed to be
  suspicious of the area.
  

>	* The radar system in the Ruskin office can't detect the presence
>of tornadoes.  The weather service's newest generation of radar has some
>detection capability, but Ruskin isn't scheduled to get that system until
>1995 at the earliest.
>
  True.  The only WSR-88D [aka NEXRAD] Doppler radar in Florida is in
  Melbourne, about 130 miles east.  Tampa is just beyond the range
  good Doppler velocity coverage, and the radar beam at the lowest
  elevation is more than 16,000 ft above the ground near Tampa.

  I'm told there is a TV station in Tampa that recently has received
  (and has been heavily touting) a Doppler radar.  _They_ had the capability
  to see the rotation in the storm.  Questions from me, "What did they see?
  Did they understand what was on the Doppler display?  Did they contact
  the NWS with that info or inform the public?  Since it was a Saturday
  morning I'm wondering how well the TV station was staffed.

[stuff deleted]	

>	But in that tornado, Pinellas residents were alerted by a tornado
>warning issued by the National Severe Storm Forecast Center in Kansas City,
>Mo.  Saturday, however, the severe storm center apparently saw nothing to
>prompt a warning.
>
   Wrong. Warnings come from the local office not SELS.  Watches come
   from SELS.

> 
>	"Tornadoes are things that we can very seldom pick up with our
>radar," said Chuck Eggleton, the weather service meteorologist on duty
>in Ruskin when tornadoes began touching down at 10:30 a.m. Saturday.
>
   The MIC at Ruskin (Mr. Balfour) was quoted on CNN as saying _even in 
   retrospect_ it was impossible to see the tornado on their
   conventional (WSR-57) radar.   Doppler is needed.

>	"Even severe thunderstorms weren't detected, and severe
>thunderstorms are something we would normally warn for," Eggleton said.
>"They just weren't that strong."
>
    Yes, these storms are very wet and so warm that hail is not likely,
    hence I can understand (caveat: I haven't seen the radar, myself)
    why they wouldn't want put out severe thunderstorm warning.  It
    seems (from discussions with relatives in the area) that flooding
    was the main concern with this weather system.

[stuff deleted]
>
>	"Details are very sketchy but some damage to one or more roofs was
>reported," the message said.  "No injuries were reported."
>

    This demonstrates that communications with local authorities were not
    up to snuff.  [speculation mode on] Perhaps they need to work on that, 
    and such communications probably would have been improved under a
    tornado watch condition. [speculation mode off]


>	Eggleton issued his first tornado warning at 11:45 a.m. after
>most of the tornadoes already had gone through Pinellas.

...quoting....
WFUS1 KTBW 031529  
FLC103-031600-  
   
BULLETIN - EBS ACTIVATION REQUESTED  
TORNADO WARNING  
NATIONAL WEATHER SERVICE TAMPA BAY AREA RUSKIN FL  
1129 AM EDT SAT OCT 3 1992  
   
THE NATIONAL WEATHER SERVICE IN TAMPA BAY AREA RUSKIN HAS ISSUED A  
TORNADO WARNING EFFECTIVE UNTIL NOON EDT  
FOR PEOPLE...  
   
IN WEST CENTRAL FLORIDA  
   
   ...PINELLAS COUNTY  
   
AND ADJACENT COASTAL WATERS  
INCLUDING THE BAY AND INLAND WATERS  
   
   
A TORNADO WAS REPORTED TO HAVE TOUCHED DOWN IN THE TREASURE ISLAND  
AREA. NO DAMAGE REPORTED. RESIDENTS IN AND NEAR PINELLAS COUNTY SOULD  
BE ALERT TO THE DANGER. RESIDENTS SHOULD STAY ALERT TO THE WEATHER AND  
TAKE COVER IMMEDIATELY IF THREATENING WEATHER DEVELOPSIND...  
   
[end quote]

   Looks to me like it was issued at 11:30.
   From their damage report:

03/1047 EDT             PINELLAS COUNTY, LARGO, TORNADO DESTROYED 23 HOMES AND  
                        DAMAGED 40 HOMES. ONE FATALITY, NUMEROUS INJURIES.  
                        REPORTED BY EOC.  
  
03/1130 EDT             PINELLAS COUNTY, PINELLAS PARK, TORNADO DESTROYED 65  
                        HOMES AND DAMAGED AT LEAST 100 HOMES. THREE  
                        FATALITIES, 75 INJURIES. TORNADO ALSO CAUSED DAMAGE TO  
                        A FEW HOUSES ON TREASURE ISLAND. REPORTED BY EOC.  
  
03/1140 EDT             PINELLAS COUNTY, CLEARWATER, POSSIBLE TORNADO KNOCKED  
                        DOWN TREES. REPORTED BY SPOTTER.  
[end quote]

   I'm not sure if the tornado began or ended at 11:30.  They may need to
   check this out more carefully.  The St. Petersburg airport obs of tornado
   had times of 11:35 and 11:40.
 
>	That warning, indicated that a tornado had beed seen somewhere in
>Florida, allowed Eggleton and other Weather Service offices across North
>and Central Florida to issue more warnings for other locations including
>Pasco, Hernando, Citrus and North Florida.

   Somewhere in Florida??  It was a lot more specific.  Treasure Island is
   very small.
  
[rest of Cermak post deleted]

Final editorial comments:

First, note how the press doesn't have the facts straight.  I see this as
a case of people not _expecting_ tornadoes so they were cautious when reports
first came in and probably did not have a lot of confirmation due to the
low visibilty.  A _Tampa_ WSR-88D probably could have given them some lead time.

-Keith
------------------------------------------------------------------------------
 Keith Brewster
 The opinions here are my own, not the University's.
 Internet: kbrews@geohub.gcn.uoknor.edu     BITNET: kbrews@UOKGCN.BITNET
 University of Oklahoma, School of Meteorology
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