829 
AXPZ20 KNHC 190050
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Thu Nov 18 2021

Tropical Weather Discussion for the eastern Pacific Ocean from
03.4S to 30N, east of 120W including the Gulf of California, and
from the Equator to 30N, between 120W and 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
0240 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: A cold front presently over 
the NW Gulf of Mexico will reach the southeast part of that Gulf 
late Fri. High pressure building in behind it combined with lower
pressure south of southern Mexico will support a gale- force 
northerly gap wind event from early Fri into late Sat morning. 
Seas will build to around 12 ft during this upcoming event. 
Please see the latest NWS High Seas Forecast issued by the 
National Hurricane Center at 
website://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more 
information.

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

The monsoon trough axis extends from along NW Colombia near 
11N76W to across southern Costa Rica, then to 10N85W to 
09N105W to 08N114W to 11N122W. ITCZ extends from 09N127W to
08N133W. It resumes at 08N135W to beyond 08N140W. Scattered 
moderate to isolated strong convection is within 60 nm of the 
ITCZ between 124W-127W. Scattered moderate convection is within 
120 nm south of the trough between 96W-101W, within 120 nm north
of the trough between 114W-120W, and also within 60 nm south of 
the trough between 96W-102W and between 111W-114W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...Updated

Please see the Special Features section above for details on the
next Gulf of Tehuantepec gale- force gap wind event.

Strong to near- gale force north to northeast winds are across 
the Gulf of Tehuantepec region, with seas to 7 ft. 

A surface 
ridge extends from high pressure of 1023 mb well west of Baja 
California southeastward across the offshore waters, with mainly 
gentle to moderate winds across the waters outside of the 
Tehuantepec region. Seas are in the 4-6 ft range across the open 
waters. Seas are 2-4 ft in the southern Gulf of California, and 3
ft or less in the central and northern Gulf of California.

For the forecast, strong to near gale north to northeast winds 
across the Gulf of Tehuantepec region will reach gale-force early
on Fri and continue through late Sat morning. Gap winds may once
again approach gale-force again in the Gulf of Tehuantepec 
region early next week as strong high pressure surges southward 
over eastern Mexico. Fresh to strong northwest to north winds may
develop in the northern Gulf of California early next week. 
Fairly tranquil conditions are forecast elsewhere through the 
upcoming weekend. 

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

Moderate to fresh winds prevail across the Papagayo region. 
Otherwise, light to gentle winds are noted north of the monsoon 
trough. Gentle to moderate southerly winds prevail south of the 
monsoon trough. Seas are in the 4-7 ft range across the majority
of the offshore waters, highest south of Panama and west of 
Colombia and Ecuador. An area of scattered showers and 
thunderstorms is observed to the south of Panama and Costa Rica
to near 05N and between 79W-86W.

For the forecast, moderate to fresh northeast to east winds will
continue in the Papagayo region through Fri. Fresh to strong
winds will return Fri night through Sat, then moderate to fresh
thereafter. Gentle to moderate winds will prevail across the
rest of the area the next several days.  

REMAINDER OF THE AREA...

A broad and weak ridge extends from a 1023 mb high pressure 
center analyzed near 29N129W southeastward to near 19N112W. A 
trough extends from 12N122W to 09N126W. A second trough is to 
the west along a position from near 11N130W to 07N136W. Latest 
scatterometer data highlighted and area of mainly fresh east to 
southeast winds within about 60-90 nm east of the first trough. 
Similar winds are near the northern part of the second trough. 
Satellite imagery shows scattered moderate convection from 13N 
to 18N between 132W-135W, and also within 60 nm of 10N131W.

Moderate to fresh trades are noted north of the convergence zone
to near 20N, with light to gentle winds north of there under the
ridge and the 1023 mb high pressure center. Gentle to moderate 
southerly flow remains to the south of the monsoon trough. Seas 
of 4-6 ft are present throughout, except for an area of slightly
higher seas of 5-7 ft located over the western part of the area 
from 14N to 20N between 128W-138W.

For the forecast, little change is expected through Fri. A cold
front is just entering the far NW corner of the area. This front 
will move across the far northern waters through late Sat as it 
weakens. It will be followed by moderate to fresh north to
northeast winds as high pressure builds in behind it. Seas of 
5-7 ft will follow in behind the cold front. An area of fresh to 
strong east winds between the first trough mentioned above and 
the aforementioned high pressure is forecast to develop from 13N
to 15N between 129W-132W beginning late Fri afternoon or 
evening. Seas with these winds are expected to build to 8 ft. By 
early Sat, these winds are forecast to diminish to mainly fresh 
speeds, with seas to 8 ft primarily due to a north swell.
 
$$
AL