St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1914-02-21
How Weather. Fore.
casts AreMade

people have an idea that there Il
something mysterious and occult
about the work of the Weather Blu
reau in forecasting the coming o.
storms. frosts and floods. Not 1e"
think that the observers must nee
essarily get their data by reading Inc
planets the stars and the moon. AS
a matter of fact the forecaster OF
the bureau foretells the coming OF
disturbances in a businesslike way
very similar to that in which a man
who has ordered shipment OF gooas
would estimate the data OF its arrlv'
al on a certain date.
Suppose q business man had order
ed q carload of pineapples from the
Hawaiian Islands. He would know
the average time it would take the
steamer to make the trip to the
Pacific port, the average time for I'M
loading and loading into refrigerator
cars. and the average number of days
to be allowed these cars for the
trip across the continent to New
York. HIS estimate, however, would
be subject to error because the steam
ship might be delayed by fog, or the
oars night meet with an accident.
Storms, like pineapples, as a rule
do not originate in the United States.
They come to us, some from the Phil
ipp.nes Japan, Siberia, Alaska, Can
ada or the Gulf of Mexico. The
Weather Bureau gets cable, tele-
graphic or wireless notice of for
ei9n storm. Station after station,
or vessel after vessel reports the
storms arrival in its neighbOrhood,
10 that the general direction and
rate OF progress can be determined
very early. In fact, the arrived OF
some storms can be foretold ten days
in advance.
The forecasters watch for the re-
gi0n Of law barometer which is the
storm center around which the winds
blow. This whirl or eddy moves
bodily forward with the general east
ward drift of about $50 miles day
IN our ATTITUDES. As the lines of
equal pressure (isobars) around the
low center crowd closer together.
the winds attending the storm in
I creases In force. The forecaster de-
termines the direction of movement
1 Of the storm and its velocity.
When weather dsturbances are
/ reported, the forecasters know from
!. experience about how long after they
will reach our Pacific Coast. For
4 example. II q storm coming from s.
] IBERIA drifts eastward around the
North Pole and reappears in Alaska,
It should appear In Washington anu
Z Oregon In about two days; should get
( to the Great Lakes in six days and
I to the Atlantic Coast in seven or
eight days.
Unexpected conditions may delay
4 storms or divert them from the
straight track just as refrigerator
car may be- thrown OF its schedule
Or be shipped by accident on q wrong
road. Some Of these storms deplete
themselves by running into reg ons
OF high barometer which are of great
{ Or magnitude and extent than the
storm itself. Some of them, how
ever. travel completely around the
world.
To keep tab on cold waves that
come into the United States from
Canada and Alaska, the Weather
Bureau studies the Canadian wealth
or reports. England sends reports
from Iceland, the British Islands and
Continental Europe, and daily re-
ports come from St. Petersburg on
the condit iOns in Russia and Siberia.
The same businesslike system used
In tracing the track of q storm ia
applied In determining the arrival of
frosts.
Flood reports are made in much
the same way. Information as to
the amount Of rainfall at the head
waters Of streams that cause floods
are covered by Geographic reports
sent by local observers. As the rain
reaches the main channel, the height
OF the water in the channel ia de-
termined by successive gag ne sta
lions. Past records establish how
much q height, say of 20 feet at
Dubuque. Iowa, will produce at DAY.
export, another station 80 m les down
the river, and at each point full al
lowance Is made for the effects of
water from tributaries, and from ad-
d.tional and local rainfall. AS a re-
suit Of These observations in the re-
cent food, the people of Cairo had
warning week or ten days in adj
vance. The Pittsburg district can
be given only IL to "a hours notice,
because q food is upon them within
- hours after heavy rain storm.
Washington, D. c., Feb. 1894.
To the Farmers:
The Director of the Bureau of the