Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-09-07
Yes, the Weuthrr
Is Changing!
By George w. Gray.


had amazingly little movement of the usual cold
sir currents. The flow, when there was any,
came from the South and warmed us still
more.
"a map Of moisture distribution over the
United States shows that there was consider
able moisture in the air even in July and early
August. And yet there was no rain.
we have theory that you can't get rain
in quantity until the air is lifted 1000 or 5000
feet. A mountain range provides this elevator
service, and it is significant that while most of
the country east of the Rockies Sweltered and
parched, the States west of and in the Rockies
received normal and in some cases better than
normal rainfall. In the Plains we get the
same lifting effect from q wedge of cold air.
Because it is heavier this cold air rides ON the
ground. pushing up the warm moist air TO
heights where condensation and precipitation
can take place. But during the recent Summer
no cold-air wedges appeared"
The Summer also was hotter than usual but
this was a result Of the dryness rather than
q cause. Most of the airs heating comes from
the conduction and reradiation of solar heat
from the warm earth. When weeks and months
pass with no clouds to shade the ground, and
with no rains to cool it, the storage Of heat i'm
comfortable.
Thus the drought produced the excessive
neat and the stagnation OF air produced the
drought-but what produced the stagnation Of
air? Science cannot answer.
WE do know that weather is controlled by
air circulation which is generated bv the
solar heating effect at the tropics and cool
ing at the poles. Weather is warm or cold
according to the temperature of the region
from which the air currents come. There
was an uncommonly warm spell last Febru-
airy because the moving areas of atmospheric
pressure entered the United States from the.
warm Pacific Ocean through our West Coast
states instead or from the ice fields Of Cam
ada. When areas of high pressure develop in
region the meteorologistS, look for an air cur
rent from that directfon--bnt they do not vet
know why the high pressure arises in one place
rather than in another.
Our first ray Of hope during the recent
drought" related Prof. Marvin, came ON Fri
day morning, August 8. It was wireless
report from the Canadian meteorological sta
ton in the Mackenzie Valley, not far from
the Arctic Circle indicating an area of high
pressure in that region. That meant, unless all
signs failed cold-air current from Canada
swooping SOutheastward."
Next day, Saturday, it was as hot az Tophet
in Washington. Elijah, in the Old Testament
story, saw a cloud the size of mans hand to
reasSure his hope and earnest endeavors for
tnAl1 buL Wd5iIIlBbDu Sk1eS promised nothing
on August 8, and the local Thermometer and
wind vane gave not even a shred of encourage
ment.
Yet the Government forecaster, Mr.. r. H,
Weightman, found all the encouragement that
he needed in the precious wireless tin from the
Robinson Crusoe who, is. living in the Barren
Lands to watch for Just such signs. The for
caster issued on that torrid Saturday morn lg
weather outlook for the period August Ii to
49," which promised these amazing changes:
North and Middle Atlantic States-Showers
Tuesday night or Wednesday, and again toward
the end Of the week. Cooler first half. with
moderate temperatures thereafter.
South Atlantic States Frequent loeal
thunder showers IN the interior throughout the
week, with moderate temperatures
ohio Valley and Tennessee Showers are in
dicated frst half of week and again toward the
end OF the week. Warm at the beginning of
the week, with cooler Tuesday or Wednesday
and with mostly moderate temperatures there
after"
I quote in full this, outlook" because it was
verified close to 100 per cent. The showers
came and SO did the thundeFstorms and the
GOODNESS. So COOL indeed. was the early part of
the week that overcoats were hauled out of
cedar chests and in many homes in the North
eastern States fires were kindled
DO you see any prospect of giving US an
outlook for a year aheade-or perhaps for a
season." / asked.
mo. not even a month";" answered the chief
OF the Weather Bureau. IF we had any way
of knowing in advance that the air circulation
this Summer would Swerve Off and 60 to Europe
and Asia We could have predicted the drought
As 1t Is. the factors that guide us in forecasting
develop only a few hours or days before the
event materiaIiSeS and SO it Is not possible to
make q scientific prediction more than few
days ahead.
ESOUR forecast is made daily for So hours