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Eastern North Pacific Tropical Weather Discussion



531 
AXPZ20 KNHC 191545
TWDEP 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1605 UTC Tue Oct 19 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 1200 UTC surface analysis and satellite imagery through
1500 UTC.

...TROPICAL WAVES...

A tropical wave that was along 84W has become diffuse and is no
longer being tracked at the surface.

A tropical wave is along 92W north of 02N to western Guatemala, 
moving westward at around 10 kt. Associated convection is
described below.

A tropical wave extends along 128W from 02N to 15N, moving 
westward at around 10 kt. Associated convection is
described below.

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

The monsoon trough axis extends from 1010 mb low pressure near
11N75W to 10N100W to 1010 mb low pressure near 11N111W to 10N125W
to 12N140W. Scattered moderate and isolated strong convection is
noted from 02N to 09N between 77W and 84W, from 07N to 10N
between 112W and 117W, from 08N to 11N between 120W and 130W,
from 10N to 13N between 132W and 136W, and from 11N to 14N
between 138W and 140W. Isolated to scattered moderate convection
is from 06N to 17N between 87W and 100W, and from 15N to 18N
between 100W and 106W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Fresh to strong N-NE winds are over the Gulf of Tehuantepec where
seas are also to 8 ft. Moderate to fresh NW-N winds are in the
northern Gulf of California. Gentle to moderate NW-N winds
prevail elsewhere across the Mexican Offshore waters. Seas are
4 to 6 ft across the majority of the remainder of the waters, 
except 2 to 4 ft in the Gulf of California.

For the forecast, winds will continue to pulse to fresh to strong
in the Gulf of Tehuantepec through the end of the week, with
mainly gentle to moderate winds elsewhere. Winds will increase
slightly to moderate to fresh offshore of Baja California this
weekend. An area of disturbed weather located a few hundred
nautical miles south of the coasts of Guatemala and El Salvador 
is producing poorly organized showers and thunderstorms. 
Environmental conditions are expected to be conducive for gradual
development of this system during the next several days, and a 
tropical depression could form late this week or this weekend 
while the system moves west-northwestward to northwestward near 
or just off the coast of southern Mexico. Seas will build 
slightly in NW swell west of Baja California through mid-week. 
Another set of NW swell will impact the same area by the end of 
the week, with a much larger set arriving this weekend. 

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

An area of disturbed weather located a few hundred nautical 
miles south of the coasts of Guatemala and El Salvador is 
producing poorly organized showers and thunderstorms. Moderate 
to locally fresh E winds are offshore of El Salvador and 
Guatemala, with light to gentle winds elsewhere north of the 
monsoon trough. Mainly moderate S-SW winds prevail south of the 
monsoon trough. Seas are mainly 4 to 6 ft in mainly southerly 
long period swell.

For the forecast, environmental conditions are expected to be 
conducive for gradual development of the area of disturbed
weather during the next several days, and a tropical depression 
could form late this week or this weekend while the system moves 
west-northwestward to northwestward near or just off the coast 
of southern Mexico and west of the area. Otherwise, little 
change is expected through the end of the week into the weekend.

REMAINDER OF THE AREA...

A cold front is located NW-N of the northern waters with fresh
winds straddling 30N, stronger north of 30N. A dissipating cold 
front is located to the east with remnant seas to 8 ft in NW-N 
swell behind it. A weak pressure pattern prevails elsewhere with 
light to gentle winds from 20N to 27N, and gentle to moderate
winds south of 20N and north of the monsoon trough. Gentle to 
moderate southerly winds prevail south of the monsoon trough. 
Seas are mainly 5 to 7 ft across the open waters in a mix of long
period northerly and southerly swell.

For the forecast, another round of northerly swell will 
accompany the cold front that will move into the northern waters
tonight, with seas in excess of 8 ft dominating the waters NW of
a line from Guadalupe Island to 14N140W by late Thu. Reinforcing
NW swell will follow over the same area through Sat. Trades north
of the monsoon trough to 25N may increase slightly by the end of
the week into the weekend as the pressure gradient tightens.

$$
Lewitsky