Evening star., 1953-09-03
BY Charles F. Barrett
Associated Press Sfoff Writer

A shift in globe-circling, jet
stream winds-50,000 feet above
the Pacific Ocean-shows signs
of breaking the biggest United
States heat wave in 20 years.
That was the word today from
the United States Weather Bu-
reau, where experts shed coats
and ties and pored over mystify-
ing charts in non-air condi-
toned offices to come up with
the good news.
Actually, they said, the cur
rent hot spell developed from a
cool air mass which came down
from Canada about August Is.
And they predicted it will end
the same way, with another cool
wave. But another heat belt
may follow.
I. r. Tannehill, chief of
synoptic reports, said this was
the worst outbreak since the
early 30s, when Washington av-
eraged better than 101 degrees
for five straight days, and Ar
kansas and Mississippi points
went up to lis.
Jerome Namaias, chief of ex-
tended forecasts, said the heat
wave was caused by a rare set
of conditions which jelled into
sort of sitdown strike by ma
ture. from the stratosphere down
to parched corn fields and
steaming city streets.
But they saw relief coming
today in the upper plains
Montana. the Dakotas and Min
nesota-and gradually spread
ing to the Atlantic Seaboard by
the week end.
Vast Area Covered.
From a scientific viewpoint,
the most unusual thing about the
heat wave was the vast area it
covered-from the Rockies to
the Atlantic-and its persistence.
Mr.. Namais, whose speciality is
gaging weather for weeks ahead
through studies of the strato-
sphere, reconstructed the situa-
ton thus;
About August 5, a pleasant
mass of cool, dry air moved down
from Canada. This was a low
lying chunk Of air. 1t extended
up for only a few thousand feet.
The winds in it circulated like
the hands of clock.
Normally, these "cool fronts"
move easterly across the country
and on out into the Atlantic,
leaving moderate weather behind.
But this one decided to just
squat. 1t settled down and spread
over the eastern two-thirds of the
Nation and stuck there.
Gradually, it warmed up for
two main reasons:
l. AS the air mass itself spread,
air from upper levels tumbled
down to take it's place. The thin
ner upper air became condensed
as it came down and this gen.
Grated heat-just as the air in a
tire pump gets hotter as it is
compressed. The air from upper
levels also was dry and it picked
up no moisture as it settled over
the continent.
2. So, there were few if any
clouds and the August sun baked
the land and the lower level air.
1t got hotter and hotter as these
conditions just remained static.
instead of changing as the
weather usually does.
Why 1t Stood Still.
And why did this heating air
mass come to Standstill for so
long?
Well. stratosphere winds nor
mally influence the movements
OF lower air masses. Unknown
to most Of us, there is what the
scientists call a jet stream of
wind rushing in generally
easterly direction around the
globe at about $4,000 feet, at
speeds up to 800 miles per hour.
This jet stream develops
gentle curves, as a result of
geographic conditions below,
such as oceans or mountains, or
because of a natural tendency
for big air or water currents to
form waves. Usually there are
about six giant waves in the
course of the jet stream around
the globe.
Normally the Jet stream
curves slide east or west, and
kick around the lower air
masses.
But for two weeks now, the
upper jet stream has been
blowing like mad in a rare state
of equilibrium. The curves were