The Wahpeton times. [volume] (Wahpeton, Richland County, Dakota [N.D.]) 1879-1919, 1914-04-30
Keeps Track Of Al Storms and
Fair Weather Areas and
Barometer Records

he can make his predictions as &C
curately in a windowless cellar as
on the top of New Works highest
skyscraper.
The private individual sees the
clouds settle on a nearby noun
tain or the rain sweep over a field
mile from his house and knows
that the storm will be on him in
few minutes. With the aid of
the telegraph the weather man
sees the same storm when it is a
thousand miles away. and not only
this storm but every other one in
the country. He knows in what di-
rection and at what speed each is
moving. and can thus calculate
with reasonable accuracy the ap-
proximate time when it will reach
any place in its route.
Twice a day, at 8 in the morn
ing and 8 in the evening. reports
are telegraphed to Washington
from about 200 observers station
ed in as many different localities
in the United States and Canada.
In these reports the observers do
not volunteer their personal opin-
ions about what is going to hap
pen. They contine themselves to a
plain statement of the actual con-
ditions at that particular moment.
the pressure, or weight. of the at
mosDhere. the temperature, the
direction and velocity of the wind,
the amount of rain since the last
report. and so forth. From this
information the Weather Map of
the United States is made up,
showing the conditions. that pre-
Since there are two maps for
each day it is obvious that by
comparing them the forester can
keep track Of the course and pro-
gress of both storms and periods
of clear weather. From that. the
next step is to predict what sort
OF weather will prevail for a day
Or two in any given locality.
This map is the basis for all
scientific weather forcasting. A
glance at it will show that it is di-
vided into thigh pressure areas
and low pressure areas" These
are technical terms used to de-
scribe the regions i'm which
the weight or pressure of
Til. atmosphere is great (high J
~ small dow. At sea leve! the
barometer. which is used To meas
Irn this weight. will register 81
Inches under normal conditions Of
tic atmosphere. When it registers
more than this, say 3O.5 OF 81. the
pressure is high when 29.5 or
less, low In way the height of
u column of mercury in a baron.
cter indicates the weight % the
air lust as. in a thermometers, it
indicates the temperature.
Low Dressures usually mean
strong winds. rain. and rising
cool. clea w>o'her. For reason
highs and lows" as they are
called. travel in a general direc-
ton from the west to east. The
forecaster notes their progress on
the map. Derceives their speed
and their route. and then predicts
the time of their arrival al any
specified point. If they travelled
IKE a ship stored by compass. al
exact course to the east. and il
they moved invariably at the same
speed. then weather forccastin.
would be simple SIM i'm arith-
metic. like calculating the tim.
when a railroad train running &c
miles an hour will arrive at 6
station 500 miles away. Bu
storms are not railroad trains
They travel in an easterly direc
ton. but they do not travel east
Their speed is liable to change
and they are affected by the pres
ence of other storms. by noun
tain ranges. large bodies of wat
er. and many other things whicl
make weather DrODhesying the
complicated science that it is. The
skeleton of the science. however
is the progress of those "highs'
and lows" eastward across the
country.
This progress is caused by the
shape of the earth and the we'll
known fact that hot air rises. The
tropical sun in the regions along
the Equator heats great masses
| Of air. which rise and drift toward
the North and South Poles. AS the
earth revolves from west to east
these masses are carried alOns
with 1T at the same speed. But. as
is also we'll known. the Equator
revolves much faster than tho
poles. which are practically sta
tionary. in much the same way a.
the rim of a wheel revolves fas.
ter than the hub. Therefore these
masses Of air. revolving at tho
same rate as the Equator. begin
as they approach the poles. tC
move much faster than the eartl
beneath them. There is thus {
constant movement of the atmos.
phere from west to east. move.
ment which becomes more mark.
ed the nearer one gets to thu
poles.
This. of course. does not NEAR
that the wind always blows from
the west. The great current flows
Fin that direction. but surface con.
tditiOns cause innumerable eddies