The herald and news. [volume] (Newberry S.C.) 1903-1937, 1921-04-01
ali, which is almost a United States

waii, which is almost a United States
sea.
weather disturbances which en-
! ter the United States accompany
lows and 'highs'-separated areas
of low and high atmospheric pressure
i as registered by the barometer
which drift in general from ives. t3
east. Atmospheric pressure is the re-
suit of the weight Of the sreat sea of
air COMPRISING the lower portion.
Naturally, in regions where the air IS
rarefed and is rising, the weigh, and
therefore the pressure, is relatively
low; where the air is contracted and
is sinking the weight is greater and
the pressure is relatively high. Heat
is the chief factor in starting air to
rise over a 'low;' and once the start
| is made the movement is contributed
to by various causes, notably conden-
sation into cloud and rain that gives
out to the air the original heat of
evaporation. Thus a sort of Chin
ney' for rising is established, and at
it's bottom the pressure is reduced.
! "The areas of disturbance lows
and shighs'-made familiar to large
numbers of people by the rough cir
cles and ellipses that indicate them on
the daily weather maps of the United
States Weather bureau, cross the con-
tinent normally in three or four days.
Usually rain or snow falls in the low
areas or slightly in advance of them.
The rains that occur in the arid parts
of the west, however, usually follow
the passage of lows
'In winter the great factory for
lows is the extensive body of warm
water south of the Aleutian Islands
and in the Gulf of Alaska. This re-
gion is kept warm by the Japan cur
rent. The air over the water is warm
ed and tends to rise. This reduces
air pressure and maintains a perma-
nent area of low pressure practically
thruout the winter. From time to time
such a large area of low pressure is
developed that fragments OF the
area, so to speak, break off, and drift
with the prevailing winds to the east.
! It is somehow like a bubble of air
under thin ice breaking off from a
larger bubble and finding its way
with the flow of the water to another
location. Normally new low is
thrown off every few days.
"The most common course Of these
lows is across the southern panhan-
die of Alaska and over British Colon
bia. to cross the Canadian border into
the United States in Alberta. For
convenience they are called Alberta
Storms A somewhat fewer number
of disturbances, called North Paci-
! fc Storms originating in the same
general region, enter between Puget
Sound and northern California. South
Pacific storms, entering south of the
northern boundary of California, are
| still less frequent; for this is the re-
gion of a more or less permanent
! high, the effect; of which is to keep
the drifting lows farther north. Now
and then low is formed in some
! section of the broad curving band OF
country stretching from Alberta thru
! Texas, including the Rocky Noun
tains, or even in the central or Gulf
states; but these occur much less
frequently than the lows which drift
in from the Aleutians.
| "In the summer the Aleutlan re-
gion which produces lows is shifted
to the interior of Alaska, and from
there the succeeding disturbances
| Qrl1C SOuLledSCWdlO, u, anu eiioSN 'AN'~N
enter the United States do SO east OF
the Rocky Mountains. The charac-
teristic path of all the lows which
enter the United States in the north
western portion of the country IS a
more or less deep dip to the south just
east of the Rocky mountains, ard Ia
ter a turn to the northeast. BY Tar
the greater number of them finally
pass from the St. Lawrence river, not
because this great valley influences
their passage, but because they are
attracted toward the permanent
North Atlantic low in the nelghbor-
hood of Iceland. 1t is as though the
bubble of air under the ice break
from it's parent bubble, meandered
about for while, and finally merged
with another large bubble.
"The high that traverse the INIT
ed States have fewer places OF origin