000
AXPZ20 KNHC 201604
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Dec 20 2022

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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: High pressure will build
southward along the eastern slopes of the Sierra Madre Mountains 
today as a western Gulf of Mexico low pressure system shifts 
eastward. As this happens, the gradient in southeastern Mexico 
will tighten as cold dense air surges southward toward the Gulf 
of Tehuantepec gap region. The resultant surge of northerly 
winds out over Tehuantepec will reach gale-force in the range of 
30-35 kt late this afternoon or early this evening, and is 
expected to last through Wed afternoon. Seas are forecast to 
build to 8-12 ft. Northerly winds will then gradually diminish 
Wed afternoon and night. Seas will subside to below 8 ft by 
sunrise Thu. Please read the latest High Seas Forecast issued by 
the the National Hurricane Center at website 
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.

Gale Warning in NW Part of area: A gale force low pressure center
well west of the area contains an associated cold front near
150W. The low and associated front will shift northeastward
through Thu, remaining NW of the forecast area. However,
southerly winds to the east of the cold front are forecast to
reach strong to near gale force, with a small area of gale force
winds on Wed north of 28N and west of 138W. Seas of 15-18 ft are
expected within the area of gale force winds in W swell. Winds
will diminish in the area Wed night, and seas will subside to
below 12 ft on Thu. Please read the latest High Seas Forecast
issued by the the National Hurricane Center at website 
https://www.nhc.noaa.gov/text/MIAHSFEP2.shtml for more details.

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

The monsoon trough axis extends from 09N84W to 06N99W. The ITCZ
continues from 06N99W to 09N124W to 09N140W. No significant areas
of convection are noted currently.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please see the Special Features section for information about an
upcoming gale event in the Gulf of Tehuantepec from this
afternoon through Wed. Currently, north winds of fresh speeds 
are in the Gulf of Tehuantepec to near 15N, where seas are 
peaking to around 6 ft.

Relatively weak high pressure is present over the area, with the 
associated gradient allowing for gentle to moderate N to NE 
winds across the Baja California offshore waters. Fresh to 
strong NNW winds are likely occurring in the southern two-thirds 
of the Gulf of California, while moderate to fresh winds prevail 
in the northern Gulf. Seas across these waters are 3 to 6 ft. 
Gentle or weaker winds and 3-5 ft seas prevail elsewhere.

For the forecast, strong northerly winds will return to the Gulf
of Tehuantepec by late this morning as strong high pressure 
surges southward over eastern Mexico. Gale-force winds are then 
expected as described above, with winds diminishing on Thu. 
Looking ahead, the next Tehuantepec gap wind event is expected 
for Fri through the weekend, with storm force winds possible on 
Fri night. In the Gulf of California, fresh to strong NNW winds
will continue through tonight.

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

Fresh northeast to east winds are in the Gulf of Papagayo 
region, while fresh east winds extend offshore of Papagayo, 
Nicaragua, and the Gulf of Fonseca, extending southwestward to 
90W. Seas are 5-6 ft over these waters. Light to gentle winds 
prevail elsewhere north of the monsoon trough along about 08N, 
with seas of 4 ft. Gentle S-SW winds and seas of 4-5 ft due to 
long-period S to SW swell are present south of the monsoon 
trough. 

For the forecast, fresh to strong northeast to east winds will 
continue to pulse in the Papagayo region through the rest of the
forecast period due to the pressure gradient related to high 
pressure ridging NE of the region. The strongest winds are mainly
expected at night and into the mornings, when seas are expected 
to build near 8 ft. Moderate northerly winds are expected today 
in the Gulf of Panama before diminishing slightly through the end
of the week. Gentle winds will continue across the Central 
American offshore waters through most of the week along with 
moderate seas.

REMAINDER OF THE AREA... 

Please read the special features section above for details on a
gale warning in the NW corner of the forecast area, from 28N to
30N between 138W and 140W. High pressure ridging prevails over 
the area between 115W and 135W from 20N to 30N. Light to moderate
anticyclonic winds and 3-6 ft seas prevail across this area.
Fresh trade winds are present from the ITCZ from 20N and west of
117W with 5-8 ft seas. A cold front is west of the area, 
described above. Fresh to strong S winds and seas of 6-7 ft are
reaching 140W now from 22N-30N. 

For the forecast, moderate to locally fresh trade winds S of 20N
and W of 120W are expected to change little through Thu. NW 
swell in the far western part of the area will migrate SE to 
near 130W by Wed night. The low pressure and cold front described
above in the special features section will bring strong S winds 
today through Wed night to waters from 22N to 30N between 134W 
and 140W, with seas reaching over 11 ft in this area. Seas of
8-11 ft will extend elsewhere north of 05N and west of 130W
through the end of the week.

$$
Hagen