000
AXPZ20 KNHC 260922
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sun Nov 26 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: A tight pressure gradient will
set up across southern Mexico between a building high pressure 
over the western Gulf of Mexico and relatively lower pressure 
over the deep tropics. This will result in strong gap winds in 
the Gulf of Tehuantepec beginning early this morning, enhanced 
by local drainage effects. Winds will reach gale force by this 
afternoon, with seas building to 12 ft. The gales will further 
increase to 40 kt by tonight into early Mon morning, with seas 
building to 17 ft downstream. Swell from the gap wind event with 
8 ft or greater will reach more than 500 nm offshore of the Gulf 
of Tehuantepec by late Mon. The high pressure weakens and shifts 
east Tue, allowing gale force winds to diminish. Another round of 
gale force winds is expected Wed and Thu.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 

The monsoon trough axis extends from 09N84W to 08N90W to 09N96W,
to 08N103W where it transitions to the intertropical convergence
zone and continues through 10N120W to 11N140W. A cluster of
moderate convection is within 75 nm S of ITCZ axis between 118W
and 120W. Scattered moderate isolated strong convection is from
10N to 13N W of 136W. 

...DISCUSSION...

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

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

A 1019 mb high pressure centered near 25N125W extends a ridge
across the offshore waters W of Baja producing light to gentle 
winds. Seas are in the 4 to 6 ft range due to NW swell. Little
change in these marine conditions is expected through early Mon.
The ridge will be replaced by a stronger area of high pressure 
building in behind a cold front moving across the region. This 
front will usher in fresh to strong NW winds off Baja California 
Norte late Mon and Mon night. Seas will also build on Mon as 
well as NW swell of 8 to 12 ft will move into the area off Baja 
California Norte, then continue to propagate off Baja California 
Sur late Mon into Tue, reaching the Revillagigedo Islands by mid
week. Winds diminish Tue, but seas in excess of 8 ft will persist
through late week as another round of reinforcing swell moves 
into the region.

Strong NW winds will follow the front across the northern and
central Gulf of California Mon night and Tue. 

OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND 
WITHIN 750 NM OF ECUADOR...
  
Gulf of Papagayo: Expect a typical nocturnal maximum of around 
25 kt across the region through early Tue morning, diminishing to
15-20 kt by mid afternoon. Seas will maximize to around 7 ft 
each morning near sunrise, and will likely build locally to 8 ft 
early Monday morning, with a more extensive area of 8 ft seas 
expected Tue morning. Moderate to locally fresh NE winds are 
expected across the Gulf of Fonseca each night through Tue. 

Light to gentle N to NE winds, and 3 to 5 ft seas are expected 
elsewhere through early Mon to the N of the monsoon trough which
has been meandering between 09N and 11N. Moderate southerly 
winds, and 4 to 6 ft seas, are forecast S of the monsoon trough.
Northerly swell generated in the Gulf of Tehuantepec will reach 
the western part of forecast zone PMZ111 (offshore waters of 
Guatemala and El Salvador) building seas up to 11 or 12 ft
late tonight through Mon night.

REMAINDER OF THE AREA... 

A cold front is over the NW waters and extends from 30N131W to 
19N140W while a reinforcing or secondary cold front stretches
from 30N135W to 26N140W. A recent ASCAT pass indicates fresh to
strong NW winds in the wake of the reinforcing front with seas of
8 to 11 ft. The fronts are forecast to merge later today as they
move eastward and approach 125W, with seas building 12 to 14 ft 
over the far NW portion of the area. 

An area of 8 to 10 ft seas in NW swell persists S of 14N W of 
125W. These seas will propagate southward across the equator 
while decaying through early Mon, just ahead of reinforcing NW 
swell currently entering the forecast area. This swell event will
cover the waters W of a line from 30N116W to 25N115W to 15N130W 
to 11N140W by Mon night with seas up to 14 or 15 ft. 

$$
GR