New-York tribune., 1903-04-30
WEATHER FORECASTING.


With the latest number of ",The United States
| Monthly Weather Review the director of the
American meteorological service introduces a
new feature. Among the charts hitherto ap-
pearing in that publication has been one show
ing the mean barometric pressure over the
whole country for month, the readings having
been reduced TO sea level. 1t is now proposed
to supplement this with two more, giving the
computed pressures at elevations of $500 and
10000 feet. Professor Frank II. Bigelow, upon
whose recommendation this innovation is made.
and who has, by an elaborate research, made
possible the preparation Of such charts. hopes
that they may In time be of assistance in sea
sonal' long range. foreCasting. Additional
data will be required. he says. 1t will be neces-
sary to know something about temperatures
and humidity at the same attitudes. Until these
are all available study of the problem cannot
bear much fruit Still, a beginning is TO be
made; and the first step is to note how far the
actual pressure for a month at various levels
differs from the average OF corresponding
periods for many years.
Up TO the present time systematic and
public predictions OF the character here con-
templated have been made under governmental
auspices anywhere In the world except in India.
Those are based on local principles, and are not
is the weight of the snowfall in the Himalayas
during the previous winter. The outcome, too,
has not been especially encouraging. What
ever be the success Of Professor Bigelow's plan,
it is already obvious that It's basis is far more
rational and his method less empirical than any
other which has yet been proposed, He does not
it is safe to assume, expect to be able to indI-
cate the exact details for any particular date
and spot, as countless "cranks" attempt to do.
The utmost which it will ever be feasible to ac-
complish in long range work, it may be conf
dently asserted, is to outline the general situa-
tion over comparatively wide areas for two or
three weeks, or perhaps Il month or more, in
advance. Yet if nothing more is accomplished
than this-a correct hint of q tendency toward
even q trif1ing excess Of heat or cold and dis
position toward an abundance or scarcity Of
ran-the benefit to the country will be enor-
I nous.
It is not incredible that a second advantage
may be secured from a more careful examina-
ton of conditions existing at two or three
standard planes in the upper air. When actual
temperatures at various elevations above the
earth are ascertained by means Of kites, it is
found that the rate of decrease with height is
not uniform. Sometimes It Is more rapid than
the established average, and sometimes it is
=
abnormal temperatures might help the fore
caster in the short range work now officially
sanctioned. At present the government meteor
ologists are bothered by several eccentricties in
the behavior of those barometric depressions
which constitute the chief feature Of all daily
maps. One is a departure from the ordinary
routes which low areas follow in crossing the
country; a second is q remarkable variation in
their speed, and the third is uncertainty about
the amount Of rain which will attend them
The last is the most serious in it's effects, but
they are all highly embarrassing. If, by mini
MIXING such uncertainties, study of the upper
air viii improve the daily forecasts it should be
pushed as far as is practicable At times the
government service while all that the present
state of meteorological science will permit per-
haps, is far from realizing the ideal of its
founders or the demands Of the public. If any
thing better is possible the country wants it.