Tropical Weather Discussion
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000
AXPZ20 KNHC 240254
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Fri Nov 24 2017

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
0245 UTC.

...SPECIAL FEATURE...

Gulf of Tehuantepec Gale Warning: Gale force winds have subsided
slightly to 30 to 35 kt across the Gulf of Tehuantepec and
downstream to near 13N96W this evening, and will gradually
shrink in areal coverage and continue with minimal gale
conditions tonight through mid-morning on Fri. Winds will then
diminish to 20 kt or less late Sat morning. Maximum seas of 14
ft near 14N95.5W area occurring this evening will subside very
slowly late tonight and early Fri to around 12-13 ft. The
resultant NE swell will propagate SW, mixing with long- period
cross equatorial swell, with seas 8 ft or higher well downstream
of the Gulf of Tehuantepec along 08N between 95W and 105W on Fri
night before beginning to subside. Expect winds 20 kt or less and
seas less than 8 ft only briefly on Sat afternoon. Strong N
winds are forecast to resume again on Sat night with gale
conditions expected just after sunrise on Sun. Latest guidance is
suggesting another 30 to 40 kt event on Sun night with the gales
diminishing by late Mon.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

The monsoon trough extends from NW Colombia near 08N77W across
Costa Rica to near 09N90W to 07N100W. The ITCZ begins near
07N100W and extends through 12N114W to 10N121W to beyond
10N140W. Scattered moderate isolated strong convection is
occurring in an area from 08N to 10N between 116W and 118W
and within 90-120 NM S of the axis between 127W and 132W.

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

See Special Features paragraph above for information on the
Gulf of Tehuantepec Gale Warning.

A modest high pressure ridge centered offshore of southern
California has weakened considerably today and is yielding
gentle and variable winds with seas of 2 to 4 ft across the
offshore waters of Baja this morning and are expected to continue
today. Seas will begin to build Fri afternoon in NW swell, and
peak at 4 to 7 ft at 13 to 15 seconds across the waters W of Baja
Fri night, then subsiding some on Sat into Sun. Long-period NW
swell in the form of 7 to 9 ft seas will reach 30N120W on Sun
night, and spread S across the waters W of Baja with 8 to 13 ft
seas at 17 to 19 seconds forecast W of Baja Mon night and Tue.

Gulf of California: Recent scatterometer passes indicated that
winds have become light to locally moderate across the entire
Gulf. This flow will continue through tonight. The pressure
gradient will relax further, with light and variable winds
expected Fri through Mon. Strong to near gale force NW flow is
expected to develop N of 26N on Mon night through Tue night,
with seas building to 10 to 11 ft across the long fetch waters.

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

Gulf of Fonseca...Fresh NW winds forecast to begin around
sunrise on Mon.

Gulf of Papagayo: Fresh to locally strong NE nocturnal drainage
flow forecast to begin tonight, with diurnally driven strong
pulses through Tue. Seas of 8 ft or greater will propagate SW to
near 08N92W on Tue.

Light and variable winds, and 3 to 5 ft seas, are expected
elsewhere through Sun night to the N of the monsoon trough which
has been meandering between 09N and 11N.  Moderate NE flow
expected N of the Gulf of Papagayo early Mon. Moderate southerly
winds, and 3 to 6 ft seas, are forecast S of the monsoon trough.

REMAINDER OF THE AREA...

A stationary front from 30N138.5W TO 28N140W will drift westward
through Fri with a broad surface low developing along the front
just W of the area tonight. The low will move NE of the area on
Fri night with the front then moving SE to extend from 30N132W
TO 22N137W by Sat evening. Scattered moderate, but weakening
convection is observed well E of the front from 17N to 25N
between 136W and 140W.

Combined seas of 8 to 14 ft at 14 to 16 seconds is currently
observed across the discussion waters W of a line from 30N126W
TO 17N140W. This long period NW swell will propagate across the
waters W of a line from 32N121W to 12N140W early Fri before
beginning to subside and shrink in area to mainly S of 15N and W
of 125W by late Sat.

$$
Cobb



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