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000
AXPZ20 KNHC 270938
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sat Aug 27 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Hurricane Lester centered near 17.9 117.4W at 27/0900 UTC moving
west or 280 degrees at 10 kt. Estimated minimum central pressure
is 987 mb. Maximum sustained wind speed is 75 kt with gusts to 90
kt. Additional strengthening is forecast during the next 48 hours.
Numerous moderate to strong convection is within 75 nm NE and 45
nm SW semicircles. Lester will continue on a general westward
motion, with an increase in forward speed during the next couple
of days. See latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMEP3/WTPZ23 KNHC for more details.

Tropical Storm Madeline centered near 14.5N 138.4W at 27/0900 UTC
moving west-northwest or 300 degrees at 9 kt. Estimated minimum
central pressure is 1000 mb. Maximum sustained wind speed is 45 kt
with gusts to 55 kt. Satellite imagery shows a cluster of numerous
moderate to strong convection within about 90 nm N of the center.
Numerous moderate to isolated strong convection is in band to the
west of center from 12.5n to 15n between 138w and 140w. Madeline
will continue on a general west- northwest motion in the next
couple of days with a decrease in forward speed, and is expected
to move into the Central Pacific tonight. Madeline is forecast to
strengthen to a hurricane once it moves well west of 140W by
Sunday night. See latest NHC forecast/advisory under AWIPS/WMO
headers MIATCMEP4/WTPZ24 KNHC for more details.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough axis extends from 12N94W to low pressure near
11N109W, then resumes near 13N118W to 12N122W to 14N127W. Clusters
of moderate to isolated strong convection are within about 90 nm
of the coast of Central America between 86W and 92W. A cluster of
similar convection is also noted near 15N94W in the Gulf of
Tehuantepec. Scattered moderate convection is from 08N to 11N
between 113W and 117W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

The outer circulation of Lester continues to impact the far
southwest portion of zone PMZ015 which includes the Revillagigedo
Islands. Marine conditions will gradually improve beginning today
as Lester moves away from this area. Moderate to locally fresh
northerly winds will persist across the pacific waters of Baja
along with 4 to 6 ft seas. In the northern Gulf of California,
moderate to locally fresh southerly winds will prevail this
morning due to the presence of a weak low pressure center. These
winds will build seas temporarily to 2 to 4 ft. Otherwise, mainly
light and variable winds will prevail with seas 2 ft or less. By
Tuesday night, marine guidance suggests building seas to 8-9 ft in
NW swell across zone PMZ011 and regional waters. In the Gulf of
Tehuantepec, northerly winds will pulse to fresh levels during the
overnight and early morning hours through early next week.

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...

Light and moderate winds will continue to prevail on either side
of the monsoon trough for the next several days, with combined
seas of 4 to 7 ft mainly in cross equatorial southerly swell.

ELSEWHERE...

A broad surface ridge covers the remainder of the area, extending
from 1019 mb high pressure near 30N130W. A weak surface trough,
likely the remnants of Kay, extends from 27N133W to 22N135W. a
recent scatterometer pass shows the wind shift associated with
this trough forecast to move west of area on Sunday. the pressure
gradient between the ridge and Lester will produce a band of moderate
to fresh winds roughly between 18N-22N, with combined seas ranging
from 5 to 7 feet. The monsoonal flow is forecast to increase to
the SE and S of Lester tonight and Sunday. Marine guidance indicates
an area of SW winds in the 20-25 kt range covering the forecast
waters from 07N-10N between 110W-125W on Sunday.

$$
GR

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