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Eastern North Pacific Tropical Weather Discussion

AXPZ20 KNHC 260247

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Aug 26 2016

Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0215 UTC.


Tropical Storm Lester is centered near 17.0N 113.8W at 0300 UTC
or about 408 nm to the south-southwest of the southern tip of
Baja California. Lester is moving W or 270 deg at 5 kt with
maximum sustained winds of 50 kt with gusts to 60 kt. The
estimated minimum central pressure is 1000 mb. During the course
of the day on Thursday Lester exhibited some organization to its
overall cloud pattern, and has changed little during the evening
hours. Satellite imagery shows numerous strong convection within
45 nm of the center in the northwest quadrant. Scattered
moderate/isolated strong convection is elsewhere within 75 nm of
the center, except 90 nm in the west quadrant. Lester is
forecast to continue moving away from the Mexican offshore
waters through tonight, and is forecast to strengthen to a
hurricane near 18.0N119.5W by Friday evening. Please read the
NHC forecast/advisory under AWIPS/WMO headers MIATCMEP3/WTPZ23
KNHC or the public bulletin under MIATCPEP3/ WTPZ33 KNHC for
more details.

A broad area of low pressure is located about 1433 nm east-
southeast of the Big Island of Hawaii. A 1008 mb low is analyzed
within this area of low pressure near 13N132W moving westward
about 15 kt. Latest satellite imagery shows that overall
cloudiness and convection has increased during the evening hours
in association with this area. Numerous convection is within 
90 nm of the low in the northwest quadrant. Scattered moderate 
to isolated strong convection is elsewhere within 120 nm of the
low in the northwest quadrant. A tight gradient between this
area of low pressure and the sub-tropical ridge to its north
is resulting in moderate to fresh northeast winds from 13N to
18N and west of 124W. An Ascat pass from 1804Z Thursday
afternoon suggested strong north to northeast winds with the
convection located northwest of the low. Strong south-southwest
were also indicated by the same Ascat pass to the south of the
low from about 08N to 10N between 132W and 136W. Seas with these
winds are within the 6 to 9 ft range. Environmental conditions
are conducive for continued gradual improvement in organization
of this system. It has a high chance for tropical cyclone
development during the next 48 hours before crossing 140W by 72


No waves at this time.


The monsoon trough axis extends from 11N89W to 09N100W to
11N108W. It resumes at 13N121W to low pressure at 13N132W 1008
mb to beyond 10N140W. Scattered moderate isolated strong strong
convection is within 120 nm south of the axis between 93W and
98W, within 120 nm south of the axis between 132W and 138W.
Scattered moderate convection is within 120 nm south of the axis
between 89W and 93W.

Scattered moderate convection is southeast of the monsoon trough
within 30 nm of line from 07N85W to 06N89W.



A narrow surface ridge extends from the NE Pacific southeastward
through 30N129W to north of Lester near 21N113W. This ridge will
change little through the upcoming weekend, and combine with the
persistent trough meandering along the Baja California peninsula
and Gulf of California, to produce mainly light to moderate
northerly flow prevailing outside of the Gulf of California.
Expect mainly light to gentle southerly flow In the Gulf of
California, except for occasionally fresh wind flow in the
northern Gulf where the pressure gradient will be slightly

High pressure in the Gulf of Mexico has weakened. The strong
gradeint associated with it providing north to northeast winds
through the Gulf. These winds are forecast to diminish to 15-20
kt by late tonight, and lower to 10-15 kt on Friday.


Light to moderate sw winds south of the monsoon trough will
continue to spread to the coastal sections through Friday, then
a light and variable onshore flow is expected Saturday and 


A broad surface ridge covers the remainder of the area,
extending from a large 1036 mb high near 49N145W. The low
pressure center that is along 132W will move westward during the
next few days. The pressure gradient between this lower pressure
and the ridge will yield fresh winds across the trade wind belt,
generally from 21N southward to near the trough, from just to
the northeast of the low center to beyond 140W. Seas ranging
from 6 to 8 feet presently in this area in mixed swell will
increase slightly to 7 to 9 feet during this time. A large area
of fresh southwesterly monsoonal flow is supporting seas of 6 to
8 feet from 07N northward between 115W and 125W. The strength
and areal coverage of these fresh winds will increase to the
south and southeast of the low center as it shifts westward
during the next few days.