River Falls journal. [volume] (River Falls, Pierce County, Wis.) 1872-2019, 1914-05-07

the rim of a wheel revolves fast
er than the hub. Therefore these
masses of air, revolving at the
same rate as the Equator, begin.
as they approach the poles, TO
move much faster than the earth
beneath them. There is thus a con-
astant movement of the atmosphere
from west to east, a movement
which becomes more marked the
nearer n get to the poles.
This, of course, does not mean
that the wind always blows from
the west. The great current flows
in that direction, but surface con-
ditions cause innumerable eddies
which are the wind we feel. In
to a low pressure area, for inst
ance, the air rushes from every
direction. Thus, if the center of
the disturbance is to the west of
us, We will have an easterly wind
as the air rushes towards this
center; when the storm has reach
ed and passed us on it's easterlv
way we will have westerly winds.
For this aso it is common to
say that west winds mean clear
weather.
The air that flows into the low
pressure area obviously must go
somewhere. Since it is coming in
from every point of the compass,
the only available place is up.
AS it rises it cools and contracts.
In the process the moisture it con
tains is condensed and we have
rain. That is, we are likely to. 1t
can not be stated too emphatically
that there are many things to be
considered which may make ex-
ceptions to the most fundamental
rules.
In regard to temperature, every
one has noticed that the rain in
winter means warm weather. in
summer cool weather. This arises
from the fact that heat travels
more easily through the clear ski
es than through clouds and mois-
ture. In the daytime heat reaches
the earth from the sun; at night
it leaves the earth to be absorbed
in the atmosphere. In summer,
therefore, when the days are long
er than the nights, the earth is be-
ing heated for a greater part of
the "a hrs. than it is being cooled.
In consequence the clearer the
weather and the easier it is for
heat to travel, the hotter it grows.
In winter the reverse is true. The
cooling time is longer than the
heating, and the clearer it is the
colder it grows.
Thus the pressure of the atmos-
phere is the key to the weather,
affecting the three vital quest
ions of rain. temperature and wind.
Many things may create an area
of low pressure and many things
may influence it's career when once
it has been created. But there
are certain general rules based on
the principles already outlined.
The weather maps tell the fore
caster the conditions of the last
few days, the telegraph tells him
Of the conditions at the moment,
and with this information he is
able to predict the conditions for
the immediate future from a stand
point very different to that of the
amateur observer, however exper-
fenced, who can form an opinion
only from TIE signs visible to his
unaided eye. 1t may, in fact, be
said that no accurate forecasts
for more than a few hours in ad-
vance are possible unless the pro-
phet is able to study a series of
observations covering a wide range
of country a few hours after they
have been taken. For it's week
ly forecasts, indeed, the United
States Weather Bureau has re-
ports not only from this country
but from abroad and at sea as
we'll.