000
AXPZ20 KNHC 202112
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
Issued by NWS Ocean Prediction Center Washington DC
2205 UTC Wed Oct 20 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 1800 UTC surface analysis and satellite imagery through
2100 UTC.

...TROPICAL WAVES...

A tropical wave is along 95W north of 04N, moving westward at 
around 10 kt. Scattered moderate to isolated strong convection 
is noted from 10N to 16N between 90W AND 100W.

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

The monsoon trough axis extends from 09N84W to 11N95W to 09N102W
to 12N112W to 09N125W to 1012 mb low pressure near 11N133W to
12N140W. 
Aside from the convection associated with the tropical wave 
mentioned above, scattered moderate to isolated strong convection
can be found from 07N to 11N between 100W and 104W, from 08N to 
10N between 118W and 134W, and from 08N to 12N W of 134W. 

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

High pressure of 1021 mb centered near 28N123W extends a ridge
across the offshore waters of Baja California producing gentle to
moderate NW to N winds. Fresh to strong northerly winds are noted
within about 15 nm of a line from 16N95W to 15N95.5W to 13.5N97W,
including the Gulf of Tehuantepec. Seas in this area are below 
8 ft. Gentle to moderate winds prevail in the Gulf of California.

For the forecast, a broad area of disturbed weather is producing
some disorganized showers and thunderstorms within a couple of 
hundred miles of the coasts of southern Mexico and Guatemala. 
Environmental conditions are expected to be conducive for gradual
development of this system during the next few days, and a 
tropical depression is likely to form by this weekend while the 
system moves slowly west- northwestward to northwestward near or 
just offshore the coast of southern Mexico. This system could 
bring an increase in winds and seas in the Tehuantepec region 
toward the end of the week. Otherwise, moderate to fresh NW-N 
winds are expected N of Punta Eugenia Fri through Sun night. Seas
are forecast to build to 10 or 11 ft in NW swell. In the Gulf of
California, mainly gentle to moderate NW winds will prevail. 
Winds will veer to the S and then SW in the northern part of the 
Gulf by Fri night as a weakening cold front approaches from the 
W.

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

As previously mentioned, a broad area of disturbed weather is 
producing some disorganized showers and thunderstorms within a 
couple of hundred miles of the coasts of southern Mexico and
Guatemala. This system has a low chance of tropical cyclone 
formation through 48 hours, and high chance through 5 days. 
Please, see the latest Tropical Weather Outlook at 
www.hurricanes.gov

Mainly gentle to moderate S to SW are expected across the
forecast area with seas of 3 to 5 ft in SW swell. By Sat night
into Sun, expect building seas of 6-7 ft in SW swell between 
Ecuador and the Galapagos Islands. 

REMAINDER OF THE AREA...

A dissipating cold front extends from 32N130W to 29N140W.
Moderate southerly winds are noted per scatterometer data SE of
the front between 130W and 140W. Seas of 8 to 11 ft in NW swell
follow the front. Another cold front is forecast to be near
30N140W by early Thu afternoon. Highest seas of 12 to 14 ft are
expected in the wake of the front. This swell event will 
propagate across the forecast waters on Fri covering the area NW
of a line from 30N125W to 23N140W. Seas in excess of 8 ft will
dominate the waters NW of a line from Punta Eugenia to 15N140W on
Sat.

$$
GR