592
AXPZ20 KNHC 160926
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1005 UTC Sun Jun 16 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 0600 UTC surface analysis and satellite imagery through
0900 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
already impacted the coasts of Guatemala and the Mexican state
of Chiapas. This pattern is expected to persist through at least
the middle of the week across northern Central America and
southern Mexico. This will increase the threat to life and
property 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 today as the focus shifts northward to northern
Central America. Additionally, dangerous surf could impact
Chiapas, Guatemala and El Salvador today through the next few
days.

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 displaced farther north than usual due to
the ongoing Central American Gyre. It now extends off the coast
of Mexico near 17N99W to 12N118W to 08N125W. The ITCZ extends
from 08N125W to 07N140W. Numerous moderate to isolated strong
convection is noted from 12N to 16N between 92W and 98W.
Scattered moderate convection is noted from 09N to 16N between
85W and 111W.

...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 and Oaxaca.
Meanwhile, moderate to fresh NE to E winds are noted in this
region with seas 6 to 8 ft.

Meanwhile, a 1029 mb high pressure is located well NW of the
region near 34N141W. Pressure gradient between this high pressure
and lower pressure over the Colorado River Valley is creating
gale force winds off the California coast. Because of that, this
is driving fresh to locally strong winds across the waters just
west of Guadalupe Island off Baja California Norte. This is also
sending NW swell across the Baja California offshore water, with
combined seas are 8 to 12 ft north of Punta Eugenia. In the Gulf
of California, light to gentle winds are noted with seas 2 to 4
ft, highest near the entrance of the Gulf. Mostly gentle to
moderate breezes and slight to moderate seas persist elsewhere
with 5 to 7 ft seas. Smoke from agricultural fires in Mexico are
causing haze particularly in the SW Mexico waters.

For the forecast, fresh to 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 before subsiding by Tue night. Meanwhile, off
southern Mexico, expect fresh SW winds and building seas starting
today 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 Central American 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 to locally strong winds across the Guatemala,
El Salvador and Nicaragua offshore waters. Seas are 7 to 9 ft in
this area within S to SW swell. Across the rest of the Central
American offshore waters, winds are gentle to moderate with 5 to
7 ft seas within S to SW swell. Strong thunderstorms continue to
impact mainly northern Central America off Guatemala, El
Salvador and Nicaragua which is bringing heavy rain and frequent
lightning. These storms could cause hazardous marine conditions.
In the Ecuador and Galapagos Island offshore waters, winds are
moderate with seas 5 to 8 ft within S to SW 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 the Central
America offshore waters through mid week. 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 1029 mb high pressure centered near
34N141W. Across waters N of 20N, winds are moderate to fresh with
NW swell propagating into the area bringing seas 8 to 12 ft N of
25N between 116W and 132W. From the ITCZ and monsoon trough to
20N and W of 120W, winds are gentle to moderate with 6 to 8 ft
seas in mixed swell. E of 120W, winds are light to gentle with 5
to 6 ft seas within SW swell. South of the monsoon trough and
ITCZ, winds are mostly gentle to moderate with 6 to 8 ft seas in
SW to S swell.

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 Tue. Seas will build
to 8 to 12 ft by Sun night into Mon, mainly north of 20N between
120W and 130W, and subside below 8 ft by Tue night into Wed. SW
flow south of the monsoon trough is forecast to continue this
morning between 90W and 115W, supporting seas of 6 to 8 ft.
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.

$$
AKR