008
AXPZ20 KNHC 152145
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Jun 15 2024

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
2130 UTC.

...SPECIAL FEATURES...

Central America and southern Mexico Heavy Rainfall Event: A
broad area of low pressure has developed over northern Central
America and southern Mexico. This weather pattern, known as a
Central American Gyre (CAG), enhances moist SW flow off the
Pacific and into the coastal terrain of Central America and
southern Mexico. This moist flow can persist for several days,
resulting in life- threatening conditions that include flooding
and mudslides. Numerous heavy showers and thunderstorms have been
ongoing for hours today along the coast of Guatemala and the
Mexican state of Chiapas, and these conditions are indicative of
a CAG. The pattern is expected to persist through at least the
middle of next week across northern Central America and southern
Mexico, with the threat to life and property increasing as the
event persists. The main areas impacted by the heavy rainfall
will be northwest Nicaragua, southwest Honduras northwest
Nicaragua, and coastal sections of Honduras, El Salvador,
Guatemala, and the Mexican state of Chiapas. Farther south,
the moist southwest flow was also causing persistent heavy
rainfall across Costa Rica and Panama, although this will be
diminishing Sun as the focus shifts northward to northern Central
America.

Again, the persistence of the moist pattern and strong onshore
flow will create very hazardous conditions to the region and
could be life-threatening. Please refer to your local
meteorological office bulletins for more detailed information.

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

The monsoon trough is well to the north of its normal position
across the southwest Caribbean and into Nicaragua, Honduras, and
Guatemala due the development of the Central American Gyre. It
extends over the eastern Pacific 14N95W to 06N125W. The ITCZ
extends from 06N125W to beyond 08N140W. Scattered moderate
convection from 06N to 08N between 77W and 87W. Numerous moderate
to isolated strong from 12N to 15N between 91W and 95W. Scattered
to moderate convection is noted from 10N to 12N between 95W and
105W.

...OFFSHORE WATERS WITHIN 250 NM OF MEXICO...

Refer to the section above for details on the Central American
Gyre.

A large cluster of showers and thunderstorms is active off
Chiapas in southern Mexico, associated with a broad area of low
pressure over the region known as the Central American Gyre.
These thunderstorms are probably causing widespread lightning,
gusty winds and locally rough seas off Chiapas. Meanwhile,
moderate NE to E winds are starting to gradually increase over
this area as the gyre develops further.

Farther north, recent scatterometer satellite passes indicate
fresh to strong NW winds approaching the waters just west of
Guadalupe Island off Baja California Norte. Concurrent altimeter
satellite data indicate combined seas are 8 ft in this area,
primarily due to NW swell. These winds and seas are influenced by
their portion between 1030 mb high pressure near 35N140W and
lower pressure over the lower Colorado River valley. This
pattern is also support gale force northerly winds farther north
off southern California, accounting for the large swell entering
the water off Baja California. Mostly gentle to moderate breezes
and slight to moderate seas persist elsewhere.

For the forecast, fresh to locally strong winds and rough seas
will persist off Baja California Norte through Mon, primarily
beyond 120 nm offshore. Large swell of 8 to 12 ft will move into
the waters off Baja California today, and persist mainly north of
Cabo San Lazaro into mid week before subsiding. Meanwhile, off
southern Mexico, expect fresh SW winds and building seas starting
tonight off Chiapas as a broad area of low pressure, continues
to develop over southern Mexico and northern Central America.
Winds and seas will increase further off Chiapas and Oaxaca
through the early part of the week as the gyre intensifies and
persists.

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

With the monsoon trough displaced farther north than usual, this
is bringing fresh winds across the Colombia and Panama offshore
waters with seas 7 to 8 ft, with the maximum seas noted off the
southern Azuero Peninsula of Panama. Across the rest of the
Central American offshore waters, winds are moderate to fresh
with 6 to 8 ft seas. Strong thunderstorms continue to impact
mainly northern Central America off Guatemala, bringing heavy
rain and frequent lightning. These storms could cause hazardous
marine conditions. In the Ecuador and Galapagos Island offshore
waters, winds are gentle to moderate. Seas are 6 to 8 ft within S
swell.

For the forecast, the broad area of low pressure known as a Central
American Gyre will cause an increase in winds, rough seas and
widespread showers and thunderstorms across much of offshore
waters through mid week. Fresh to strong winds and rough seas in
the Gulf of Panama will diminish by early Sun, as the focus of
strong SW winds and rough seas shifts farther north from
Nicaragua to Guatemala. Farther south, seas to 8 ft in S swell
will continue around the Galapagos Islands through Tue.

...REMAINDER OF THE AREA...

Broad ridging dominates the waters north of the ITCZ and monsoon
trough, anchored by a 1030 mb high pressure near 35N140W.
Moderate to fresh winds prevail across waters north of the
monsoon trough and west of 115W with seas 6 to 9 ft. East of
115W, gentle to moderate winds are noted south of the monsoon
trough to 05N. Seas are 5 to 7 ft across the rest of the Pacific
waters.

For the forecast, strengthening high pressure centered NW of the
area will dominate waters west of 120W into the weekend. Fresh to
strong winds from the California Channel Islands southward are
likely to dip south of 30N at times through early next week.
Seas will build to 8 to 12 ft by Sun night into Mon, mainly north
of 20N between 120W and 130W. SW flow south of the monsoon
trough is forecast to continue tonight between 90W and 115W,
supporting seas of 6 to 8 ft. Similar winds and seas are likely
to return there by the end of the weekend into early next week.
Thunderstorms will persist near the monsoon trough and east of
110W or so through the next couple of days. Seas to 8 ft will
hover around 03S near the Galapagos Islands through the weekend.

$$
Christensen