000
AXPZ20 KNHC 191607
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 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 1200 UTC surface analysis and satellite imagery through
1520 UTC.

...SPECIAL FEATURES...

Gulf of Tehuantepec Gale Warning: High pressure will build
southward along the eastern slopes of the Sierra Madre Mountains
starting late 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 the Gulf will reach 
gale-force in the range of 30-35 kt on Tuesday night, and is 
expected to last through Wed night. Seas are forecast to build 
to 8-11 ft. Northerly winds will be strong to near gale-force 
during Wed afternoon and night. Seas will subside to about 9 ft 
late Wed night. 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 10N75W to 09N86W to 
06N102W. ITCZ extends from 06N102W to 08N118W to 05.5N133W to 
beyond 06N140W. Scattered moderate convection is noted from 04N
to 09N E of 89W to the coasts of Panama and Colombia, and within
90 nm north of the ITCZ between 111W and 130W.

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 strong
gap winds to near 30 kt extend across the Gulf of Tehuantepec to
near 13.5N, where peak seas are 8 ft.

Relatively weak high pressure resides is over the area
this morning and producing light to gentle N to NE winds 
across the Baja California offshore waters, Gulf of California, 
and waters of southwest Mexico to near Acapulco. Seas across 
these waters range 3-4 ft, except for lower seas of 1-2 ft in the
Gulf of California. 

For the forecast, strong northerly winds will continue through 
in the Gulf of Tehuantepec through early this afternoon, at which
time the pressure gradient in eastern Mexico relaxes. Seas will 
lower to below 8 ft by late this morning. Conditions will rapidly
improve on Mon afternoon. Strong northerly winds will return to 
the Gulf of Tehuantepec by Tue afternoon as strong high pressure 
surges southward over eastern Mexico. Gale-force winds are 
expected with this event starting Tue evening and continuing 
through Wed night. Seas may build to near 12 ft Tue night into 
Wed. Conditions will improve on Thu afternoon briefly before a 
strong gap wind gale event begins on Fri. This next event could 
very well reach storm force. Please monitor the latest marine 
forecasts for future updates regarding this next upcoming Gulf of
Tehuantepec gap wind event.
 
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 Tue evening 
before diminishing. Seas are expected to reach 6-8 ft Tue 
morning. The high pressure will weaken on Wed allowing for these 
winds to diminish to fresh speeds.

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, extending westward to 90W. Seas are peaking at  
7-8 ft over these waters. Light to gentle variable 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 due to S 
to SW swell are found south of the monsoon trough. Gentle or 
weaker winds and slight to moderate seas are noted across the 
central American offshore waters. 

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 strong winds are mainly expected at night and 
into the mornings. Seas are expected to build near 8 ft at the 
time of the strong winds. Moderate to locally fresh northerly 
winds likely tonight and Mon night in the Gulf of Panama. 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 1022 mb high near 35N125W. The
southern tail of a cold front has moved into the NW waters, and
extends along 30N136W to 27N136W. Overnight scatterometer data 
showed mostly fresh southeast to south winds N of 24N and east of
the approaching front to near 135W. Presently fresh winds are
occurring within 90 nm E of the front. Seas are 6-8 ft in W-NW 
swell across this area. Elsewhere, light 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 southerly winds south of the ITCZ. 
Seas are in the range 5-7 ft, except for slightly higher seas of 
6-8 ft in the far western part of the area from 05N to 16N W of 
134W 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 Wed night. 
The long-period swell in the far western part of the area will 
migrate E to near 120W by Wed night. Looking ahead, high pressure
will shift eastward while strengthening through Wed night. The 
gradient between the high pressure and relatively low pressure in
the tropics should allow for fresh trade winds to exist S of 20N 
and W of 120W through Wed night. A complex low pressure system 
and associated cold front will approach the NW waters on Tue 
night into Wed, bringing strong to near gale-force southerly 
winds N of 26N and W of 137W on Wed afternoon. A low probability 
presently exists for these winds to reach sustained gale-force. 
Large swell producing seas possibly to 17 ft will also propagate
through this area Tue night through Wed night, then begin to 
slowly subside on Thu.

$$
Stripling