AXPZ20 KNHC 250246

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Tue Oct 25 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
0200 UTC.


Hurricane Seymour is rapidly intensifying and it is expected to
become a major hurricane on Tue. At 25/0300 UTC, Seymour is
located near 15.5N 112.6W, moving west or 280 deg at 14 kt. A west to
west-northwest motion is expected through Tuesday. A turn toward
the northwest should occur by Wednesday. Maximum sustained winds
have increased to 90 kt with gusts to 110 kt. Minimum central
pressure is 976 mb. Numerous strong convection is noted within 60
NM of the center of Seymour while scattered moderate to strong
convection is seen elsewhere from 12N to 18N between 110W and
115W. Although the forecast track keeps Seymour just outside of
the Mexican offshore zones, fresh to strong winds and seas in the
8-10 ft range are expected to affect the southern part of zones
PMZ023 through tonight and PMZ015 through late Tue. For additional
details on Seymour, refer to the latest NHC forecast/advisory
under AWIPS/WMO headers MIATCMEP5/WTPZ25.

A gale warning will remain in effect for the Gulf of Tehuantepec
during the next 48 hours, as strong northerly winds will persist
throughout the week across this region. By Thursday night into
early Friday morning, the aerial extent of the gale force winds
will increase as high pres builds across the western Gulf of
Mexico. At that time, seas are expected to build to 10-14 ft.


The monsoon trough extends across the Gulf of Panama near 08N79W
to 07N90W to 10N102W. The ITCZ axis stretches from 11N129W to 10.5N134W
to 11N140W. Scattered moderate convection is noted near 06N84W,
and within 120 nm S of trough between 92W and 95W.



See special features for details on the Gulf of Tehuantepec gap
wind event. High pres of 1019 mb is centered near 28N121W and is
producing light anticyclonic winds across the waters W of the Baja
California Peninsula. Combined seas are 4-6 ft N of 24N. Seas
increase to 8-11 ft across parts of forecast zones PMZ023 and
PMZ115, particularly S of 20N...including the Revillagigedo
Islands, due to the presence of Hurricane Seymour located just S
of these forecast areas. The high pres will shift slightly N-NE
during the next 24 hours. This will result in moderate NW winds
across the offshore waters.

Inside the Gulf of California, mainly gentle southerly winds
prevail across the north half, while gentle N to NW winds prevail
across far southern portions. By tonight, gentle to moderate NW
winds will dominate all the waters S of 27N extending SE to
between Los Cabos and Las Tres Marias Islands. On Tuesday, as the
high center shifts farther N-NE, NW winds will spill down the
entire length of the Gulf of California.


Gulf of Papagayo: Winds will pulse over the Gulf of Papagayo over
the next couple of days. Winds will peak near 20 kt during the
late night and early morning hours and diminish to near 15 kt
during the afternoon and early evening hours.

Elsewhere gentle to moderate S to SW winds are noted S of the
monsoon trough, while mainly gentle W to NW winds prevail N of
the monsoon trough. Combined seas are in the 4 to 6 ft range,
primarily in long period SW swell which is dominating the offshore
waters. These marine conditions will persist over the next few


A weak ridge dominates most of the north waters N of 20N, and is
producing mainly light and variable winds between 20N and 30N.
Outside Seymour, two weak low pres centers are noted S of 20N, one
is near 18N119W and the second one is near 15N128W. Seas to 9 ft
are within nm SE and 120 NE quadrants of the low pres located near
18n119w. A pair of altimeter passes confirmed the presence of
these sea heights. Seas over this area are forecast to subside
to less than 8 ft by Tuesday.

A cold front is over the NW waters and extends from 30N134W to
28N140W. Moderate to fresh SW winds are noted N of 28N ahead of
the front to 128W. This front will become stationary by early Tue
morning extending from 30N135W TO 27.5N140W. At the same time...a
second and stronger cold front will be approaching 30N140W. these
fronts are forecast to merge by Tue evening. SW winds of 20-25 kt
and seas of 8-9 ft are expected NW of a line from 30N132W to
27N140W by early Tue morning. A new set of long period NW swell
will follow the merging cold front building seas to 10 ft by Tue