Evening star. [volume] (Washington, D.C.) 1854-1972, 1893-11-06

The isobars are still more nearly circular
than before and are greater in number and
closer together, a condition on the map that
SHOWS there Is a marked difference between
tne atmospheric pressure at the center and
that at tie edges of the storm, or, as Il is
technically expressed, that there exists a
marked barometric gradient" This gradi-
emit Is sharpest where the lines are nearest
eacn other and severe wind storms are al
most certain result of such a condition,
because the air, by reason of the great off
aerence OF pressure, will flow with high
NeIoclues INTO the region of low pressure
Inc wind directions. marked by the ar
rows on the map, show the manner in which
tne alr nows into the region of low pres
sure not directly into its center, but toward
that center and around il in a direction on
poslte TO that of the movement of clock
hands. The flow of the air northward from
sne gun sun continues. The precipitation
caused by this storm DEVELOPMENT has been
very extended, embracing over three-fourth
OF the entire area of the United States.
Monday, April 4, = am.
The movement Of the storm during the
preceding twelve hours has been mora
sharply northward than would have been
expected. judging from the general move
ment Of storms. The pressure at the center
is still lower than before, and in fact We
nave shown on this map a typical storm or
cyclone of great intensity, extending its in
nuence over a circular area fully 500 miles
in diameter
An examination of subsequent charts will
show that the storm is now at its height
the pressure at the center having fallen
from Zy.5 on the evening of April 2 TO al
AT the time OF this observation. This great
increase IN the energy of the storm is gem
erally assigned to be directly a consequence
OF the expansion and cooling of the large
quantities OF warm and moist air which the
initial action Of the storm drew into itself
In this case principally from the gulf re-
gion. The result of the cooling has been
the condensation of vapor, the precipitation
OF enormous quantities of water and the
nberation OF great quantities of heat pre-
vlously latent in the vapor before conden-
sation. This heat tends to prevent the al
ready overheated air from cooling as fast
as IL otherwise would, and thus prolongs
ana even adds TO the intensity of the un-
equal distribution of temperature and
pressure throughout the great extent of the
atmospheric masses involved. Rain and
cloudy. skies still accompany the storm con-
dition, and high winds prevail throuehout
tne iake region and Missouri valley.
Monday, April 4, pm.
The storm during the past twelve hours
mas moved directly northeastward, with a
slight increase in pressure at the center
and with corresponding diminution in
energy. The isobars are now closest To-
gether and the barometric gradient steepest
over the northwestern quadrant of the
storm. throughout which high wind velocf-
ties prevail. Westward Of the storm center
marked fall of temperature has occurred
over the region inclosed within the heavy
dotted line, and the temperature has risen
over less extended area TO the eastward
and in front of the advancing storm.
The rise of temperature in front of an
advancing storm and the sharp fall of tenn
perature in the rear, occurring with or fol-
lowed by rapidly clearing weather, are
Characteristic Accomplishments of gensral
storm Developments, and the Occurrences ef
n he int
sons takes place in this manner. A condi-
ton of high barometer, accompanied bv
fair weather, is advancing closely upon the
rear OF the storm from the Pacific coast
Throughout the period covered by these
maps condition of high pressure and fair
weather has prevailed over the South At
lanuc coast, with little change of position,
ana TO this circumstance may be attrfb-
uted the sharp DETECTION of the storm track
TO the northeastward.
Tuesday, April 3. nm.
The distance traversed by the storm-cen-
ter during the period between this and the
preceding map was nearly double that OF
any previous twelve-hour movement the d.
rection being stin northeastward the high
on the South Atlantic coast still remaining
stationary. A slight widening of the distance
between the isobars indicates a gradual
alininution OF energy and the advance of
the storm is being followed by rapicly
clearing conditions. the high barometer over
the extreme west being clearly defined and
crowding slight northwestern low" visit
PIE on TINS and the preceding map, far to
the northward.
The region of rainfall is stin very extend
ed, especially TO the southeast of the storm
center, but an examination of the symbols
VIII snow that clear or only partly cloudy
skies already prevail throughout the greater
part of this region-that is, the rain shown
probably occurred during the early part of
the night The fall of temperature follow
ing closely in the rear Of the storm still af-
fects large area. The absence of observa-
tons northward of the great lakes prevents
charting all the features of the storm pro-
erosion. A new area of low pressure is Just
appearing over the western Gulf coast
Tuesday, April 8, pm.
The position of the storm is now so far to
the north that observations are available
only throughout its southern portion. The
energy, however, is clearly seen TO be
greatly lessened. but high wind velocities
prevail along the New England and North
Atlantic coasts. The movement of the
low in the far northwest is still In a
nearly easterly direction, and so far as the
few observations in this region SHOW the
storm is not accompanied by rainfall. due,
seemingly, to the natural deficiency OK
moisture in the atmosphere OF these re-
gions.
The low" on the gulf coast has advanced
slightly northeastward, and the influence OF
the high atmospheric pressure existing over
the Rocky mountain region extends far to
the eastward. The occurrence of rain under
these conditions has been over scattered
areas, with regions of fair weather in be-
tween. The area of marked fall in tempera-
ture has increased In extent and also in the
amount of fall, while over a second region
farther to the northwest the temperature
has risen from 10 degrees to % degrees. This
latter rise Of temperature follows naturally
after the sharp fall occurring over the
greater part of this region some twenty
four hours before.
Wednesday, April q, nm.
This last mao of the series shows the
storm central in the extreme northeast over
the Gulf of Saint Lawrence, having moved
in all a distance of fully 1900 miles in sew
enty-two hours. The rate of movement dur
ing the last two days was much more rapid
than the first day. averaging $50 miles per
day, which is over thirty-five miles per hour.
Storm conditions of this character over the
United States and the temperate zones in
general always move from theWest eastward.
Some portions of their path will be north
eastward, some southeastward, but the
movement is always from the western por-
ton of the country toward the eastern.
The cause of this direction of motion is
connected with the circumstance that the
earth revolves on it's axis from west TO east
and that the general movement OF the air