The National tribune., 1890-05-08
THE WEATHER.
Some Lessons from the Louisville Tornado.
ny LIEUT.. }. P. FINLEY, US. SIGNAL SERVICE.

ny LIEUT.. }. T. FINLEY, u, s. SIGNAL SERVICE
Correspondence invited suggestions desired
and information nhecTfuIly furnished Every cT
fort employed to make this Bureau OF practical use
10 The readers Of fHE NATIONAL TnfnUNE All
communications should bc addressed Weather
TnK NArioSAL TRIBUNE Office. Washington. d. q. /
Tornadocs are associated with the develop.
ment and progress Of cyclouic disturbances
They arc ono of tho features OF these great
movements Of the atmosphere. cyclone is n
peculiar circulation Of air, which embraces vast
area under the influence of one general move.
ment from LEFT 10 right about a center where
the baromotric pressure is lowest aud increases
thCrcfrOm all sides TO the circumference or
outer limit Of this disturbance, where the baro.
metric pressure rises TO a maximum at the cen
ter Of an nnt-cycloue. The distance from the
center Of the cyclone 10 tho center Of tho anti.
cyclone varies from 500 10 1000 miles The
circulation of air in an anticyclduc Is contrary
10 that IN "a cyclone, viz. from right TO left. As
rule tho cyclones of the United States reach
this country from the West Indies or the North
Pacific Ocean. With this brief introduction
about cyclones, we will proceed concerning the
Louisville tornado. 80 called, by inviting atten.
ton 10 the fact that or the 2Jth of March 1890
cyclone appeared of the Oregon aud Wash.
ington coast moving rapidly eastward By the
morning of tho 26th 10 was central in Southern
Kansas Up 20 this time the atmospheric cir.
cnlatiOu of the cyclone had brought into its
hopper, so 10 speak, only the dry temperate
air of the mountain aud plateau regions, and
az "a result there was but little cloud formation
or precipitation. On the north aud west the
precipitation fell as snow, aud on the sou TIA aud
east as rain. As tho center Of the cyclone ap.
proached the Mississippi Valley the degree Of
heat and moisture increased enormously in the
south half, especially the southeast quadrant
OF the disturbance. This was the natural con
sequence of cycOnic circulation, aud the pro,
grcssive movement of the cyclone into n region
whore the movement of the air about the center
OF lowest bar0metric pressure brought into that
aren the warm, moist atmosphere of the Gulf
aud as 1t moved further eastward similar heat
aud moisture from the Gulf Stream.
On the afternoon Of March q the cyclone
was central near Springfield, III. The heat aud
moisture was now being rapidly brought into
the cyclOnic center from the Gulf and on the
north side there came into il great quantities
of cold, dry air Snow, with temperature be.
low freezing, prevailed in the north west quad
rant while rain, with temperatures over 7Oo.
obtained in the southeast quadrant of the
cyclone. IL was showing, with temperature
Of 800, at Des M0nes, Iowa, and raining, with
temperature of 100, at Nashville, Tenn
AT about p IN. tornadoes and other violent
local storms began developing in southern
Missouri aud southern Illinois, aud AZ the
center Of the cyclone dow moved eastward
these storms extended into Tennessee, Ken
lucky and southern Indiana.
These local disturbances embraced the full
catalog OF this class of atmospheric meteors.