000
AXPZ20 KNHC 180715
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Tue Oct 18 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 0600 UTC surface analysis and satellite imagery through
0700 UTC.

...SPECIAL FEATURES...

Offshore of Southern Mexico: A trough of low pressure located a 
few hundred nautical miles south of the southern coast of Mexico
continues to produce a broad area of showers and thunderstorms as
described below. Environmental conditions appear conducive for 
additional development, and a tropical depression is likely to 
form in the next two to three days while the system moves 
generally west-northwestward, parallel to the southwestern coast
of Mexico. This system has a medium chance of tropical cyclone 
formation through 48 hours and a high chance through 5 days. 
Regardless of development, increasing winds and building seas 
will be possible offshore southwestern Mexico by the end of the 
week into the weekend. Please refer to the latest NHC Tropical 
Weather Outlook at https://www.hurricanes.gov for more details. 

...TROPICAL WAVES...

The axis of a tropical wave is near 76W/77W near the Pacific
coast of Colombia north of 04N, moving west at around 10 kt.
Scattered moderate isolated strong convection is noted from 03N 
to 09N between 77W and 80W.

The axis of a tropical wave is near 96W north of 08N, moving 
west at around 15 kt. Nearby convection is described below.

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

The monsoon trough extends from northern Nicaragua near 12N87W to
08.5N120W to 12N136W to 11N140W. Isolated to widely scattered 
moderate to strong convection is noted from 08N to 19N between
85W and 105W, from 08N to 13N between 100W and 113W, and from 05N
to 14N between 118W and 140W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Please refer to the Special Features section above for details on
possible tropical cyclone development offshore southwestern
Mexico later this week.

Moderate NW-N winds are noted offshore Baja California north of
Cabo San Lazaro as well as in the Gulf of California north of
27N. Light to gentle winds are noted elsewhere offshore Mexico,
except moderate to fresh well south-southwest of the Gulf of
Tehuantepec near a tropical wave which is described in greater
detail above. Seas are mainly 4-5 ft across the open waters,
except 5-7 ft offshore Oaxaca and Chiapas. Seas are 3 ft or less
in the Gulf of California.

For the forecast, other than the possibly developing trough of
low pressure, fresh to strong N winds in the Gulf of 
Tehuantepec will develop by mid-week, peaking to at least near 
gale-force Wed night through Thu night with building seas. 
Elsewhere, gentle to moderate winds and moderate seas will 
prevail through next week. 

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

Gentle to moderate S-SW winds prevail across the offshore waters,
locally fresh beyond 200 nm offshore Guatemala. Seas are in the 
4-6 ft range from Costa Rica southward, and 5-7 ft elsewhere.
Scattered showers and thunderstorms are offshore Colombia ahead
of a tropical wave, as well as from western Costa Rica northward.

For the forecast, moderate to occasionally fresh S-SW winds will
prevail south of the monsoon trough. Gentle to moderate winds
north of the monsoon trough will diminish to light to gentle Wed
night, except pulsing to moderate offshore southern Nicaragua and
in the Gulf of Papagayo into the upcoming weekend. Moderate seas
in S-SW swell will dominate the waters, building offshore 
Guatemala by mid-week due to a Gulf of Tehuantepec gap wind 
event.

REMAINDER OF THE AREA...

A cold front extends from 30N129W to 25N137W. A 1019 mb high is 
centered to the east near 29.5N124W. A set of NW swell with 7-9
ft seas is lagging behind the front over the far NW waters. The 
pressure gradient between the area of high pressure and the 
monsoon trough is supporting moderate to locally fresh winds 
north of the monsoon trough to near 19N and west of 125W along 
with 6-7 ft seas. Gentle to locally moderate winds are elsewhere 
north of the monsoon trough along with seas of 4-6 ft seas. 
Moderate to fresh winds are south of the monsoon trough to the
Equator and east of 110W per recent ASCAT scatterometer data, 
with gentle to moderate southerly winds elsewhere south of the
monsoon trough. The moderate to fresh winds south of the monsoon
trough are supporting seas in the 7-9 ft range east of 110W. 
Seas of 4-6 ft prevail over the remainder of the discussion 
waters. 

For the forecast, the cold front will drift east across the
north-central waters, eventually dissipating over the next day 
or so. The set of long period NW swell will propagate across the
NW waters, with another set of NW swell by the end of the week. 
A set of SW swell with seas of at least 8 ft may breach 03.4S and
the Equator by mid-week.

$$
Lewitsky