923
FXCA20 KWBC 021907
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
306 PM EDT Fri Oct 02 2026

Forecast Bulletin 02 October 2026 at 1900 UTC:

Today (Friday), locally heavy rainfall will remain a concern
across southern Mexico and Pacific Central America. Over the
weekend, heavy rain and a few strong thunderstorms are expected
over Hispaniola, while moisture shifting toward the western Gulf
will increase the rainfall threat along eastern Mexico by Sunday.

An upper-level low near the southern Bay of Campeche will drift
west to northwest through Sunday. Rainfall will favor its moist
periphery, with convergence and terrain helping focus convection
across southern Mexico. Deep moisture extending from the western
Caribbean into the Gulf will gradually shift westward. By Sunday,
southeasterly flow will transport this moisture toward Tamaulipas
and Veracruz, increasing the potential for heavy rainfall where
coastal convergence and lifting along the eastern slopes overlap.
Farther west, afternoon convection will favor the Sierra Madre
Occidental and adjacent interior areas, while moisture and terrain
continue to support locally heavy storms over Oaxaca and Chiapas.

Over Hispaniola, a mid- to upper-level trough will deepen toward
the island and develop a closed circulation nearby by Sunday.
Relatively cool air aloft above a warm, moist boundary layer will
support increasing instability. Daytime heating, mountain
circulations, and sea-breeze convergence will favor thunderstorms,
with the greatest coverage expected Saturday afternoon and evening
over Haiti and the western to central Dominican Republic. Locally
heavy rainfall may continue into the night. Additional storms are
possible Sunday, although decreasing moisture across eastern
Hispaniola should reduce overall coverage.

Forecast soundings support vigorous afternoon updrafts,
particularly over Haiti. Pockets of drier air above the moist
lower levels could strengthen downdrafts, which could allow a few
storms to produce strong winds. Brief small hail is possible in
the strongest cells, although confidence is lower than for strong
gusts. The expected profile favor localized episodes of strong
convection.

For the 48-hour period from 12Z Saturday, October 3, through 12Z
Monday, October 5, rainfall totals of 50-100 mm are possible in
the wetter portions of central and northern Haiti and the western
to central Dominican Republic, with localized maxima that could
surpass 100 mm. Moist easterly flow over exposed slopes and
repeated development along terrain and convergence boundaries
could concentrate these higher totals. The placement and
persistence of the heaviest cells remain uncertain. Heavy rainfall
could produce flooding and localized landslides in steep terrain,
with runoff affecting downstream valleys even where local rainfall
is lower. Saturday should contribute most of the weekend
accumulation.

Elsewhere in the Greater Antilles, daytime heating and local
convergence will sustain showers and thunderstorms over Cuba,
Jamaica, and Puerto Rico. The nearby trough will support
instability over Puerto Rico through Saturday, while moisture
becomes less consistent Sunday. Lingering moisture over eastern
Cuba and Jamaica will support locally heavy convection. Across the
Lesser Antilles, passing trade-wind showers will prevail, with
increasing moisture favoring the southern Windward Islands later
in the period.

The monsoon trough and moist Pacific inflow will continue to
support convection along Pacific Central America. Upslope flow
will favor locally heavy rainfall over Costa Rica and Panama Today
and Saturday. Farther northwest, low-level convergence and
developing cyclonic flow offshore will favor renewed convection
from Pacific Nicaragua toward El Salvador and Guatemala during the
weekend, with terrain and repeated storms determining the heaviest
accumulations.

Across northwestern South America, moist Pacific flow converging
along western Colombia and rising over the coastal terrain will
sustain locally heavy showers and thunderstorms, particularly
Today and Saturday. Over northern Colombia and Venezuela,
afternoon heating and local convergence will remain the main
triggers for convection, with available moisture controlling its
coverage.


Tropical Waves Initialized at 12 UTC:
TYPE SOF  INIT  03/00 03/12 04/00 04/12 05/00 05/12 06/00 06/12
TW  15N   38W   41W  44W   48W  52W   55W   57W  60W  62W
TW  17N   69W   71W  74W   77W  79W   81W   83W  85W  87W

Alamo...(WPC)


$$