625
FXCA20 KWBC 171916
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
315 PM EDT Fri Oct 17 2025

Forecast Bulletin 17 October 2025 at 1900 UTC:

The Bahamas and Caribbean:

A dissipating cold front extending over Hispaniola into the
Yucatan Peninsula will continue bringing some precipitation in
portions of the Greater Antilles, including Jamaica, Hispaniola
and Puerto Rico and over the Leeward Islands from today into
Saturday as deep moisture inflow continues over land. In addition,
enhanced upper-level divergence with an upper-level trough with
base over Hispaniola is expected.  Periods of heavy rainfall are
expected for portions of the Leeward islands with enhanced
low-level moisture convergence, a slight risk for severe weather
exists for this region. Over Jamaica a low-level trough extending
to mid-levels is expected to bring heavy rainfall. In Hispaniola
thunderstorms are expected as low- and upper- level conditions are
favorable for the development of convection.

Some precipitation is also expected over southern Bahamas from
today through Saturday, with another cold front extending into the
region. As the cold front moves south from Saturday to Sunday,
more precipitation is expected over the Bahamas and the Greater
Antilles, including eastern Cuba and Hispaniola. As the front
becomes stationary, precipitation is expected to continue through
Monday.

A tropical wave currently located around 55W is expected to bring
thunderstorms and heavy rainfall over Trinidad y Tobago and the
northeastern Caribbean coast of Venezuela from Saturday to Sunday.
As the tropical wave propagates westward over Venezuela
precipitation will increase in the region through Monday.

Another tropical wave over the central tropical Atlantic,
currently being monitored by the National Hurricane Center (NHC)
with a 30% chance of tropical formation in the next seven days is
expected to move into the region by Monday, bringing rainfall and
thunderstorms, particularly for the Windward Islands from Sunday
to Monday.

Tropical South America:

Across tropical South America, showers and thunderstorms will be
observed each day. The primary drivers will be low-level moisture
convergence, diurnal heating, and local effects. Most of the
precipitation from today through Monday will be over the Pacific
coast of Colombia across tropical South America, showers and
thunderstorms will be observed each day, as long-fetch Pacific
moisture feeds into the region, rainfall totals from 20-45mm are
expected each day.

Thunderstorms and periods of heavy rainfall are expected from
today through Monday over the Maracaibo region in Venezuela and
the northeastern Andes region in Colombia due to the presence of
low-level convective induced troughs, enhanced moisture advection
and additional support from mid-level troughs.

Mexico and Central America:

A broad area of low pressure offshore of southern Mexico,
currently being monitored by NHC with a 40% chance of tropical
development in the next seven days, will bring some precipitation
from through Sunday particularly over portions of Oaxaca and
Guerrero, however the heaviest rainfall is expected to remain
offshore.

Another area that should expect some precipitation from today
through Sunday is the eastern coast of the Yucatan Peninsula with
enhanced low-level convergence and moisture advection from the
Caribbean.

A low-level trough is expected to move into eastern Mexico from
Sunday to Monday, increasing low-level moisture convergence over
Veracruz. Total accumulations are expected to be around 20mm -
45mm.

Rainfall is expected along the Pacific coast of Central America,
from today through Sunday, due to the presence of the monsoon
trough from Guatemala through Nicaragua. The main driver for
precipitation in this region is the enhancement in moisture and
onshore flow due to the monsoon trough, the presence of a broad
low-pressure within the monsoon trough and mid-level trough
propagating along the Pacific coast of Central America, starting
over Costa Rica today and moving northwestward towards El Salvador
through Sunday.

Over Guatemala, and southern Mexico, an enhancement in low-level
moisture convergence is expected to cause heavy rainfall with
total accumulation reaching 40-80mm.

Some precipitation is expected over eastern Honduras and Nicaragua
from today through Monday due to moisture advection. More
precipitation is expected towards the end of the forecast period,
as a low-level trough approaches Nicaragua. Although the heaviest
precipitation will remain offshore from Sunday to Monday, rainfall
may increase over land from Monday to Tuesday.

Over Costa Rica and Panama heavy rainfall is expected from Sunday
through Monday, with total accumulations around 40mm-80mm as a
broad area of low pressure develops at lower level, and upper
level divergence is enhanced by an upper level trough.


Positions of Tropical/Easterly Waves Initialized at 12 UTC
TYP SOF INIT 18/00 18/12 19/00 19/12 20/00 20/12 21/00
TW  14N  41W   44W   48W  53W  55W   57W   60W   65W
TW  11N  55W   58W   61W  65W  68W   70W   72W   75W

For the latest available charts please visit:
https://www.wpc.ncep.noaa.gov/international/crb_day1-3.shtml

Rivera-Torres...(WPC)
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