Evening star. [volume] (Washington, D.C.) 1854-1972, 1895-08-17
The Tracks of Storms for the Past
Twenty Years.
WHERE THEY ORIGINATE
A Valuable Work Performed by the
U. S. Weather Bureau.
TWENTY-FOUR AUG SITS
Prepared by the U. S. Weather Bureau.

Prepared by the U. S. Weather Bureau.
The first vivid impression of any student
on approaching the practical use of the
weather maps, as they present the seeming
ly endless FORKS and combinations of the
temperature and pressure lines, is one of
confusion. This feeling is also sure to be
attended by one of encouragement, and
probably the impulse to abandon the task
OF seeking an underlying plan is more pow
erful to many persons than the incentive,
which depends upon curiosity, to know
what it all really means
The storms of the United States follow,
year after year. a series of tracks, not ca
PRECIOUS. but related to each other by very
well defined laws.
The Storm Line.
The positions of these tracks have been
determined carefully for the United States
by studies made in the forecast division of
the weather bureau on the long series of
maps that have been made during the past
twenty years. The line that the central
point of a high area or that the center of
a storm makes i'll passing over the country
from west to east is laid down on individ-
ual charts, these are collected on group
chart. and from this the average line pur-
sued can be readily described. The ac-
ccmpanying chart shows the general result
of a study of tracks of storms in the United
States.
1t indicates that. in general. there are two
sets of lines running west and east. one set
over the northwestern boundary, the lake
region and the st. Lawrence valley; the
other set over the middle Rocky mountain
districts and the gulf states. Each of these
Is double. one for the highs and one for
the lows. Furthermore. there are lines
crossing from the main tracks to join them
together showing how storms pass from
one to the other. On the map the heavy
lines all belong to the tracks for the highs,
and the lighter lines to the lows. Let US
trace them somewhat in detail. high
reaching the California coast may cross
the mountains near Salt Lake, and then
pass directly over the belt of the gulf states
to the Florida coast or it may move fur
ther northward, cross the Rockeys In the
state of Washington, up the Columbia river
valley; then turn east, and finally reach the
Gulf of st. Lawrence. We may speak of
the lower track as the southern circuit. and
the upper as the northern circuit. These
are located where they are by the laws of
general circulation of the atmosphere and
the configuraton of the North American
continent. This movement of the EighS
from the middle Pacific coast to Florida or
to the Gulf of st. Lawrence Is confined to
the summer half of the year-April to Sep
TENDER, inclusive.
In Winter.
In the winter months, on the other hand,
the source of the highs is different. though
they reach the same terminals. In the
months, October to March inclusive, many
highs enter the United States near the 115th
meridian and flow south, along the Rocky
Mountain slope, into the southern circuit,
and thus reach the south Carolina coast; or
else they turn more abruptly eastward and
move in the northern circuit over the lakes