AXPZ20 KNHC 242204
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 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
Based on 1800 UTC surface analysis and satellite imagery through
...GALE WARNING IN THE GULF OF TEHUANTEPEC...
The wind speeds in the Gulf of Tehuantepec just weakened to less
than gale-force during the last few hours. Expect N to NE winds
of 20 to 30 knots during the rest of the afternoon and evening,
until just before sunrise on Saturday. The sea heights will
reach 10 feet. Expect wind speeds of 20 knots or less from just
before sunrise on Saturday until just before sunrise on Sunday.
The wind speeds will increase to N 20 to 25 knots just before
sunrise on Sunday. The sea heights will be less than 8 feet
until midday on Sunday. Expect Gale-force winds to return to the
Gulf of Tehuantepec around midday on Sunday. The sea heights may
reach 11 feet, with the arrival of the gale-force winds.
INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 09N84W TO 08N95W TO 09N104W. THE ITCZ
CONTINUES FROM 07N104W TO 08N120W TO 09N128W TO BEYOND 10N140W.
SCATTERED MODERATE ISOLATED STRONG FROM 07N TO 09N BETWEEN 79W
AND 83W...WITHIN 60 NM OF ITCZ BETWEEN 110W AND 112W...AND
WITHIN 60 NM OF ITCZ BETWEEN 123W AND 125W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
A weak ridge continues across the offshore waters of Baja
California producing mainly light to gentle NW winds and seas of
3 to 4 ft. Seas will begin to build late this morning through
this afternoon in NW swell, and peak at 4 to 7 ft at 13 to 15
seconds across the waters W of Baja tonight, then subside some
on Sat into Sun. Long-period NW swell in the form of 7 to 9 ft
seas will reach 30N120W by early Mon morning, and spread S
across the offshore forecast waters W of Baja with 8 to 13 ft
seas at 17 to 19 seconds Mon night and Tue.
Winds will increase very slightly over the weekend, mainly due
to daytime heating. However early on Monday, stronger high
pressure will begin to build across the region from the NW and
act to increase NW winds to 20-25 kt across the waters N of 26N,
including the Sebastian Vizcaino Bay, by the late afternoon and
Gulf of California: Overnight scatterometer data indicated
gentle to locally moderate winds across the entire Gulf. This
flow will continue through tonight. The pressure gradient will
relax further, with light and variable winds expected through
Mon. Strong to near gale force NW flow is expected to develop
across the northern Gulf Mon night, with fresh to strong winds
spreading southward across the central and southern portions of
the Gulf through Tue night. Seas will quickly build to around 8
ft across the northern Gulf by Tue morning and then 6-8 ft
through central portions by Tue night.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
Fresh to locally strong NE winds are occurring across and
downstream of the Gulf of Papagayo this morning, with the
assistance of the nocturnal drainage flow. Seas have built to 6-
7 ft downstream of the gulf. Expect a typical nocturnal maximum
of around 25 kt across the region through early Mon morning,
diminishing to 15-20 kt by mid afternoon. Seas will maximize to
around 7 ft each morning near sunrise. Moderate to locally fresh
NE winds are expected across the Gulf of Fonseca each night
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 southerly
winds, and 3 to 6 ft seas, are forecast S of the monsoon trough.
REMAINDER OF THE AREA...
A cold front is along 140W from 24N to 26N. A 1012 mb low
pressure center is near 28N144W. The low center is forecast to
move NE during the next 24 hours, and end up well to the north
of the discussion area. The cold front is forecast to reach from
30N136W to 22N140W tonight, and extend from 30N129W to 20N139W
by Sat night. Fresh to strong southerly winds are expected ahead
of the front, but mainly N of 26N. A reinforcing or secondary
cold front will reach the far NW corner of the area by Sat
morning, followed by fresh to strong NW winds and seas up to 10
or 11 ft. The fronts are forecast to merge on Sun as they move
eastward and approach 125W.
Overnight altimeter data indicated seas of 10 to 14 ft from 20N
to 27N W of 134W while seas of 8 ft or greater in long period NW
swell are propagating across the waters NW of a line from
30N121W TO 12N137W TO 12N140W. This swell event will begin to
subside, with seas 8 ft or greater mainly S of 15N and W of 125W
by late Sat. At that time, another pulse of NW swell is
expected to reach the far NW waters.