000
AXPZ20 KNHC 232213
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Wed Jun 23 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.

...SPECIAL FEATURE...

Gale Warning: A 1008 mb low is analyzed near 12N95W along a 
tropical wave that extends from 04N to coastal Mexico along 95W, 
moving west at 10 to 15 kt. Scattered moderate to strong 
convection is noted within 150 nm in the southwest semicircle of 
the low pressure, and within 180 nm in the northeast semicircle 
of the low pressure. Environmental conditions appear conducive 
for development of this system, and a tropical depression is 
expected to form during the next couple of days as the 
disturbance moves west-northwestward at about 10 mph. This system
is expected to be near the coast of southern or southwestern 
Mexico this weekend, and interests in those areas should monitor 
its progress for development. In addition to strong winds and 
large seas near this system, the main weather impact will be the 
potential for heavy rainfall and flooding along the mountainous 
coastline from Guerrero to Jalisco. This is in the same general 
area that experienced heavy rainfall from Dolores a few days ago.

...TROPICAL WAVES...

A second tropical wave extends from 05N to 16N along 108W, 
drifting west. Scattered moderate convection is noted from 11N 
to 14N between 106W and 110W.

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

The monsoon trough extends from 09N84W to 1008 mb low pressure
near 12N95W to 11N122W. Segments of the ITCZ extend from 11N122W
to 12N125W to 11N130W, and from 10N132W to beyond 09N140W. In 
addition to the convection mentioned in the Special Features and 
Tropical Wave sections, scattered moderate convection is active
within 60 nm of the ITCZ west of 135W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

A ship observation in the Gulf of Tehuantepec confirmed 20 kt
east winds are already in place to the north of the area of low
pressure developing farther south near 12N95W. A recent altimeter
satellite pass indicated seas were already reaching 8 ft in the
Gulf of Tehuantepec. Recent scatterometer satellite passes 
indicated light to gentle SE breezes elsewhere off southern
Mexico, where moderate SW swell persists. Farther north, gentle
to moderate NW breezes are evident as well, with 4 to 6 ft seas
in a mix of SW and NW swell.

For the forecast, the gale warning is in effect for the offshore
waters from western Oaxaca to Michoacan effective Thu night and 
Fri. This is related to the developing low pressure currently 
well south of the Gulf of Tehuantepec. There is a high chance 
this low will develop into a tropical depression over the next 
couple of days. If this happens, gale conditions or higher are 
possible off Colima, Jalisco and south of Cabo San Lucas Fri 
night through Sun, then approaching Socorro Island Mon. 

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

A recent scatterometer satellite pass showed fresh to strong E to
SE winds off Guatemala, funneling between the mountainous 
coastline and the developing low pressure forming south of the 
Gulf of Tehuantepec. Light to gentle breezes are noted elsewhere,
with slight to moderate seas in SW swell. 

For the forecast, the fresh to strong winds off Guatemala will 
diminish through tonight as the low pressure developing south of
southern Mexico continues to move to the WNW. Fresh NE gap winds
will pulse through the Gulf of Papagayo tonight and Thu. 
Moderate to occasionally fresh SW swell will impact the waters 
off Ecuador, Colombia and into western Panama and Costa Rica 
through Sat. Elsewhere, light to gentle breezes and slight seas 
will persist.

REMAINDER OF THE AREA...

A high pressure ridge extends across the waters north of 20N and west
of 125W and is centered on a 1025 mb high near 35N142W. The 
pressure gradient between this area of high pressure and lower 
pressure within the monsoon trough/ITCZ is supporting gentle to 
moderate winds north of 08N and west of 125W. A trough is
analyzed near 130W, separating the monsoon trough and the ITCZ, 
where winds near 20 kt within 120 nm to the west of the trough
and seas are 7-8 ft. Winds and seas will diminish through the
latter part of the week in this area.

$$
Christensen