The weekly Thibodaux sentinel and journal of the 8th Senatorial District. [volume] (Thibodaux, Lna. [i.e. La.]) 1875-1898, 1888-01-07
THIBODAUX, SATURDAY,
NO. %.

the varying air pressure. All barome-
ter readings on these maps are there
fore corrected and reduced to sea-
level.
+ The terms "high" and '1ow," seen
on the map, represent areas Of high
and low pressure. A line encircling
the term '.high' shows that that Sec
tiOn of the country has an air pressure
greater than the surrounding sections,
and the figures found at the terminal
| of these isobars show tho height to
tenths of inches.
Water flows from higher to low
er level, and SO the air flows from
high to a lower pressure. II there is a
"high" of 80 inches in the northwest
and a Glow" of 80 over the South
Atlantic states, brisk northwesterly
winds with falling temperature would
prevail in all states, from Tennessee
to southern Dakota.
A 'high'', consisting of dense cool
air, must, necessarily, lower the tenn
perature of all sections in its vicinity
| and over which it passes since the air
from such an area flows outward to-
wards lower pressure.
The Glow" OF cyclOnic disturbance
may spring up anywhere if the condi-
tions are favorable. The initial cause
of a 'low", a higher temperature in
the central than the exterior part of
some local temperature disturbance,
causes an initial ascending current
of air (since heated air rises),
and this heated air is replaced by the
low currents and DETECTED by the
earth's rotation, giving rise to a gyra-
tory motion of the atmosphere cau-
sing the ''low."
Tho general tendency of these areas
is eastward, and since their power and
progression depend greatly upon the
moisture in the air, it is very likely
that the majority of the ''lows" formed
in the northwest are attracted by the
chain of lakes between the United
States and Canada and move out
through the st. Lawrence valley.
The rain area is generally found in
advance OF Il ''lOw', and upon the in
tensity of the latter greatly depends
the section of the country affected
thereby. If there is SLOW" OF 29.
covering Dakota and ''high" Of 80.
on the Maine coast, it is very probable
that the section north of Tennessee
and west OF Pennsylvania to Minnesota
will be affe, ted thereby in having pre-
vailing easterly winds, higher temper
ature and cloudy weather, with rain
about 500 mills east and southeast
from the center of the depression.
General storms are more frequent
| o,,H vv-a1 of tho LOTT foil
winter and early spring, (the cold wave
season,) while the local storms are Pc
culiar to the warm season.
When local rains are predicted tor
this OF any other State, the idea that is
meant to be conveyed is that the To-
cal conditions are favorable to produce
excessive cloudiness and consequent
rains, but that there is no general eye
clonic disturbance affecting the section.
The isostherms dotted lines) on the
map, do not follow the curvature of the
"highs" and ''lows" except during the
cold season when "high forms" it will
be noticed that the centre of such an
area is often the region of the lowest
temperature. At the terminal of those
dotted lines will be found the degree
of temperature of the section.
By observing the positions Of the
''highs" and "lows", their formation,
as we'll as the curvature of the various
lines of lesser pressure, their tendency
to move in certain directions, the pre-
vailing wind, and state of weather, the
meteorological conditions of the United
States can be readily understood, and
| why in some sections it is cold or warm
or why local or general storms prevail.