000
AXPZ20 KNHC 192136
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon Dec 19 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 1800 UTC surface analysis and satellite imagery through
2020 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: High pressure will build
southward along the eastern slopes of the Sierra Madre Mountains
on Tue 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 on Tuesday evening, and is expected to last through midday
Wed. Seas are forecast to build to 8-12 ft. Northerly winds will
then gradually diminish Wed afternoon and night. Seas will 
subside to about 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.

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

The monsoon trough axis extends from 10.5N75W to 09.5N84W to
06.5N93W to 06.5N103W. The ITCZ extends from 06.5N103W to 
08N120W to 06N131W to beyond 08.5N140W. Scattered moderate 
convection is noted from 03.5N to 09N E of 89W between 78W and
88W, and within 90 nm north of the ITCZ between 103W and 131W.

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. Currently fresh gap
winds to around 20 kt extend across the Gulf of Tehuantepec to 
near 14.5N, where peak seas are 7 ft.

Relatively weak high pressure resides over the area this
afternoon and is producing light to gentle N to NE winds across 
the Baja California offshore waters, gentle to moderate NW winds
across the Gulf of California extending to the waters offshore of
CAbo Corrientes. Seas across these waters range 3-4 ft, except 
for lower seas of 2-3 ft in the Gulf of California. 

For the forecast, fresh northerly winds will continue to diminish
across the Gulf of Tehuantepec through tonight, as the pressure 
gradient in eastern Mexico relaxes.  Strong northerly winds will
return to the Gulf of Tehuantepec by late Tue morning as strong 
high pressure surges southward over eastern Mexico. Gale-force 
winds are then expected as described above. Looking ahead, the
next Tehuantepec gap wind event is expected for Fri, with gales
commencing by sunset Fri and continuing through the weekend.

Meanwhile, strong NW winds are expected to develop in the Gulf 
of California tonight as strong high pressure builds over the 
western U.S. These strong winds will continue across all but far 
northern portions of the Gulf through Wed morning before 
diminishing. Seas are expected to reach 6-8 ft by late Tue 
morning. The high pressure will weaken on Wed allowing for these 
winds to diminish to fresh speeds, then gradually diminish
further through the end of the week.

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

Strong northeast to east winds are present in the Gulf of 
Papagayo region. Late morning scatterometer data showed fresh
winds to around 20 kt extending offshore of Papagayo, Nicaragua,
and the Gulf of Fonseca, extending southwestward to 90W. Seas 
are 6-8 ft over these waters. Light to gentle winds prevail 
elsewhere north of the monsoon trough along about 08N, with seas 
of 4 ft. Light to gentle S-SW winds and seas of 4-5 ft in S to 
SW swell are found south of the monsoon trough. 

For the forecast, fresh to strong northeast to east winds will 
continue in the Papagayo region through the rest of the week 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 tonight through Tue 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... 

The area W of 120W remains under the control of relatively weak 
high pressure, centered on a 1025 mb high near 35N125W. The
southern tail of a cold front has moved into the NW waters, and
extends along 30N136W to 28N136W. Afternoon scatterometer data 
showed mostly fresh southeast to south winds N of 27N and east 
of the front to near 130W. Seas are 6-8 ft in W-NW swell across 
this area. Elsewhere, light to moderate NE-E winds are present N
of 20N and W of 120W. Seas over this area are 5-6 ft. Moderate 
to locally fresh winds are noted from the ITCZ to 20N and W of 
115W, with gentle to moderate southeasterly winds south of the 
ITCZ. Seas are in the range 5-7 ft, except for slightly higher 
seas of 7-9 ft in the far western part of the area from 04N to 
16N W of 130W in NW swell. Elsewhere, moderate or weaker winds 
with slight to moderate seas are prevalent. 

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 120W by Wed night. A complex low pressure system and 
associated cold front will approach the NW waters on Wed night 
into Thu. A strong pressure gradient to the E of the front will
produce strong to near gale-force southerly winds across the far
NW waters beginning Tue night, and shift eastward to N of 22N 
and W of 137W on Wed afternoon before lifting northward out of 
the area through Thu morning. Gale-force winds are expected just 
to the W and NW of 30N140W during this time, with a low 
probability of these gales moving into the local NW waters. Large
swell producing seas 16 to 17 ft will also propagate through 
this area Tue night through Wed night, then begin to slowly 
subside on Thu.

$$
Stripling