126
AXPZ20 KNHC 180353
TWDEP

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0405 UTC Tue Jun 18 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 0000 UTC surface analysis and satellite imagery through
0300 UTC.

...SPECIAL FEATURES...

Central America and southern Mexico Heavy Rainfall Event:
The broad area of low pressure over SE Mexico and western Central
America has moved into the Bay of Campeche and has been
designated as Potential Tropical Cyclone One (PTC One) in the
Atlantic basin. The broad system draws abundant moisture from
the Pacific Ocean into the coastal terrain of Central America
and southern Mexico. This pattern will continue at least through
late week, enhancing heavy rainfall and strong thunderstorms.
This can cause 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. The main areas impacted by the heavy rainfall will
be northwest Nicaragua, southwest Honduras, El Salvador, coastal
sections of Guatemala and the Mexican state of Chiapas.
Additionally, dangerous surf conditions will impact these
coastal areas through the next few days. Please refer to your
local meteorological and emergency management office bulletins
for more detailed information.

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

A monsoon trough extends from the northwest coast of Oaxaca State
of Mexico through 08N120W to 07N141W. There is no ITCZ east of
140W. Numerous moderate to scattered strong convection is
observed from 14N to 17N between 93W and 98W. Scattered moderate
convection is noted from 10N to 13N between 90W and 106W, and
from 06N to 11N between 111W and 123W.

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

Refer to the Special Features section above for details on heavy
rainfall.

The persistent enhanced SW-W flow south of southern Mexico
associated with PTC One results in fresh to near gale-force SW
winds. This was confirmed by a recent scatterometer (ASCAT)
satellite pass. The strongest winds are likely associated with the
strong convection in the area. Seas in these waters are 8-11 ft.

A 1026 mb high pressure system over the North Pacific dominates
the remainder of the area. The pressure gradient between the
aforementioned ridge and lower pressures due a low pressure off
southern California result in fresh to strong northerly winds
west of Guadalupe Island, as seen by ASCAT. Northerly swell is
producing seas of 9-11 ft in the area described. Elsewhere in the
Baja California offshore waters, moderate or weaker winds and
seas of 6-9 ft are prevalent. The scatterometer data also showed
moderate to locally fresh southerly winds and seas of 2-5 ft in
the Gulf of California. In the remainder of the Mexican offshore
waters, moderate or weaker winds and moderate seas are
prevalent.

For the forecast, fresh to strong SW to W winds, rough to very
rough seas, and numerous heavy showers and strong thunderstorms
will impact the offshore waters of southern Mexico through Fri,
primarily off Chiapas, Oaxaca and southeastern Guerrero States.
Dangerous surf is also anticipated through Thu along the coastal
areas of this region. Farther north, fresh to locally strong NW
winds and very rough seas will persist off Baja California Norte
through Tue morning, primarily beyond 120 nm offshore. NW swell
in these waters mainly north of Cabo San Lazaro will gradually
subside through Tue night. From Wed evening through Fri morning,
fresh to strong NW winds and rough seas should develop near Baja
California Sur, including waters near Cabo San Lucas as pressure
gradient increases.

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

Refer to the Special Features section above for details on heavy
rainfall.

Potential Tropical Cyclone One, centered in the Bay of Campeche,
continues to induce a strong monsoonal flow, resulting in fresh
to locally near gale-force SW to W winds along with seas at 8 to
11 ft. Scattered showers and thunderstorms are evident in the
offshore waters of Guatemala and El Salvador. Moderate to fresh
SW winds with 5-8 ft seas and isolated thunderstorms are
occurring offshore of Nicaragua. Moderate to locally fresh
southerly winds and seas of 6-8 ft are occurring south of 01N.
Elsewhere, moderate or weaker winds and slight to moderate seas
prevail.

For the forecast, fresh to strong SW to W winds, rough to very
rough seas and numerous heavy showers and strong thunderstorms
will persist through Fri across the offshore waters of northern
Central America. Dangerous surf is also anticipated through Thu
along the coastal areas of this region. Farther south, rough seas
in moderate to large southerly swell will continue near the
Galapagos Islands and offshore of Ecuador through Tue night.

...REMAINDER OF THE AREA...

Refer to the ITCZ/Monsoon Trough section for convection in the
region.

The enhanced monsoon flow supports fresh to strong S-SW winds
south of the monsoon trough to 06N and east of 120W, as shown by
a recent ASCAT pass. Seas in these waters are 7-10 ft. A 1026 mb
high pressure system near 31N145W dominates the waters north of
the ITCZ and monsoon trough. The pressure gradient between this
ridge and lower pressures off southern California result in fresh
to strong northerly winds and seas of 9-11 ft north of 27N and
east of 127W. Moderate to locally fresh N-NE winds and seas of
6-9 ft are found north of 15N and west of 115W. Elsewhere,
moderate or weaker winds and moderate seas prevail.

For the forecast, the high pressure and related ridge will
gradually weaken starting midweek, which should allow winds and
seas north of 20N to slowly subside after midweek. will dominate
waters west of 120W into the weekend. East of 110W, SW to W winds
are going to increase to between fresh to strong with seas
building to between 8-11 ft by Tue. Scattered moderate
convection is expected to continue near the monsoon trough
through at least midweek. Seas of 7-8 ft will hover around 03S
west of the Galapagos Islands through Fri.

$$

Chan