The San Francisco call., 1899-08-01

of high barometer (pressure 80 go inobasl oen
trail in latitude Al degrees north Iongiture 40
degrees west. slightly to the north and vves,
therefore, of its position during July Around
this area of high barometer the winds circr
late in a positive direction, l. e. in the ear,a
direction the hands of a clock the wind
arrows of the Pilot Chart showing the p~eya-
lence OF northerly winds between the area %
maximum pressure and the Pacific Coast or
the United States. northeasterly and easterIv
winds (the northeast trades the southern
slope; souheasterly, southerly and southwest
erly winds to the west OF the center and west
erly winds along the northern slope In the
immediate neighborhood of the center ITSELF
frequent claims and light variable winds will
be experienced. The probable limits OF the
trades are shown upon the chart Over the
eastern half of the ocean they will be found
blowing with an average force of ( tBeaufort
scale), varying in direction from north north
east along the meridian of 130 degrees west to
east northeast in midocean. and to east soueh-
east beyond the meridian of $50 degrees west
especiaily along and to the southwark of the
parallel of 10 degrees north Frequent vari-
abes will also within this region
NortherIy and northwesterly winds will re-
place the trades between the American coast
and line drawn from 40 degrees north. 135 de
grees west. to 10 degrees north, 1l0 degrees
west. Southerly winds, becoming southwest-
erty as we leave the equator VIII prevail from
the American coast westward to 120 degrees
west and from the line to the parallel 0f ID
degrees north. Between 10 degrees north AMI
Is degrees north the prevailing direction Of the
wind will be easterly The winds of this rs
gion. especially of its more northery portions
will be subject to frequent interruptions by
tedious calmS.
Occasional cyclonic storms of no great in-
tensity may be encountered between the par
alleIs of 10 degrees north and 20 degrees north
along the sailing route from San Francisco On
the line and return. Heavy thunderstorms are
also likely to occur along the coast of Mexico
and Central America and in the doIdrums or
region between the trades. Squally weather
may be expected in the vicinity Of the Ha-
waiian Islands.
The area of low barometer-The prevailing
westerly winds-An eastward proongation of
the area of low barometer central over conti-
ACia lriD Sea fr1re
inches). The presence OF this low gives rise
10 a belt of variable winds mainly from south,
southwest and west. extending from the Aleu-
tian Islands to latitude 40 degrees north. These
winds will have no great strength. owing to
the weakness of the barometric gradient OF
slope their average force being less than
the Beaufort scale. Gains Will he frequent
throughout this belt. especially between l55
degrees west and 40 degrees east
Cyclonic and antt-cyclonic circuIatons-Tem-
porary of high and low barometer will
be found moving in a general easterly dtrec-
tion across the ocean. Around the areas Of
high barometer the winds circulate in the same
direction as the motion OF the hands OF Watch
(anti-cyClonic): around the areas of low barom-
eter in the opposite direction tcyclonic). In
advance of an snti-cyconic area, high, the
weather is dry. the barometer rises. and the
thermometer falls. while the general direction
Of the winds is polar or westerly: in advance
NJ a cvcIonic area or low IL is damp the
barometer falls. and the thermometer rises.
while the general direction of the winds 10
equatorial or easterly. The eastward passage
of an anti-cyclone is generally marked by the
occurrence of light winds and fair weather; OF
foul weather. The progress of the latter is
generally confined to the region between the
parallels of 80 degrees north and 50 degrees
north Their occurrence is slightly more fire.
quent during August than during July Out OF
224O observations within the belt specified (55
degrees north to 80 degrees north. and between
125 degrees west and AS degrees east. 10 per
cent gave a wind force above 3. and per cent
above beaufort scale). as compared with
per cent and per cent respectively, for the
month of July.
Monsoons-The area of low pressure central
over Asia maintains its depth 2e.50 inches).
The southwest monsoon may be. expected to
blow steadily throughout the China Sea, ac-
companied by hot. sultry weather and abun-
dant rain, especially along the western coast
of Luzon.
Typhoons-The average occurrence Of ty-
phoons for the month ofAugust, derived from
the observations during the thirteen-year
period 1sS4-1S96 is between 5 and 4. The region
throughout which these storms are most fire.
ouent and the tracks followed by the several
classes are shown elsewhere upon the chart
Fog-Fog and mist will be prevalent along
the American coast. and occasional fog may be
expected north of the 40th parallel from the
American to the Asiatic coast. Frequent fog
probable above the belt shown on the chart