462
FXCA20 KWBC 061928
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
328 PM EDT Mon Oct 06 2025

Forecast Bulletin 6 October 2025 at 1915 UTC:

Synopsis:

Hurricane Priscilla and the development of a monsoon low is
expected to bring heavy precipitation through much of the
southwest portions of Mexico, Guatemala, and El Salvador over the
next few days. On the east coast of Mexico, a Tropical
Upper-Tropospheric Trough (TUTT) and an associated low-level
induced trough is expected to heavily impact precipitation
patterns across the Yucatan Peninsula and Veracruz. Significant
moisture will be brought onshore into this region, and high
precipitation totals are expected beginning today and continuing
throughout the week. In the Bahamas and the Caribbean, a low
pressure system will continue bringing precipitation into the
Bahamas, before moving west into northern Cuba in the middle of
the week. In the Lesser Antilles and the Virgin Islands, a
tropical wave (AL95) is being monitored for potential
precipitation impacts late in the week and into the weekend.

Mexico and Central America:

Moisture associated with Hurricane Priscilla will continue
bringing precipitation into the southeastern coast of Mexico,
particularly in the Jalisco/Colima region today. Priscillas
circulation will bring moist onshore flow, which with orographic
enhancement, will support high precipitation totals of up to
30-60mm today. After today, Hurricane Priscilla is expected to
continue moving northwestward, remaining off the west coast of
Mexico throughout the next few days. The residual moisture flow
associated with Priscilla, however, is expected to enter into the
southern tip of Baja California Sur today and Tuesday. Moderate
and locally heavy precipitation is expected for this area, with
precipitation totals expected to reach a maximum of 15-30mm on
today.

In the Bay of Campeche region, a potent Tropical
Upper-Tropospheric Trough (TUTT), with an associated low-level
induced trough is expected to significantly impact the regions of
Veracruz, Tabasco, and the Yucatan Peninsula in Mexico, along with
most of Guatemala and Belize over the next three days. With the
TUTT being situated over the Bay of Campeche, substantial
upper-level divergence is anticipated in the east coast of the
Yucatan Peninsula through the forecast period. Strong easterly
low-level flow and high moisture content of precipitable water
values over 65mm, will converge onto the east coast of this area,
where the associated low-level induced trough will be located.
This will bring heavy precipitation from the Gulf of Honduras to
northern Quintana Roo in Mexico, with precipitation totals
reaching a maximum of 40-80mm today and 30-60mm on Tuesday.
Locally higher amounts are possible in isolated areas.

The induced low-level trough will then retrograde westward
reaching the Bay of Campeche on Wednesday morning, and orographic
effects will shift the low-level flow from an easterly flow, to a
northeasterly flow into most of Veracruz and the western parts of
Tabasco. With significant moisture still present, and strong
low-level flow, much of Veracruz should expect very heavy
precipitation beginning Tuesday through late into the week.
Precipitation maxima of 25-50mm is expected on Wednesday and
35-70mm is expected on Thursday.

The presence of the monsoon trough just south of the coast of
Guatemala and El Salvador, along with a developing low-level
cyclonic circulation, which the National Hurricane Center has
given a 60% chance of developing into a tropical cyclone in the
next seven days, will dictate much of the conditions in the region
in the coming days. The broad low-level circulation will bring in
moisture from the Pacific into southern Guatemala and western El
Salvador, and will then propagate westward. Precipitation at this
point is forecast to be heavy and will affect the southern coast
and interior portions of Mexico, with precipitation totals
reaching up to 20-45mm on both Wednesday and Thursday.

Bahamas and the Caribbean:

A low pressure system just off the east coast of Florida will
inject moisture into the Bahamas over the next few days. A subtle
upper-level trough, also reflected in the mid-levels, will be
conducive to upper-level divergence and instability in the eastern
islands of the Bahamas. Easterly lower level moisture flow, along
with moisture convergence will aid in the generation of
precipitation over much of the northern Bahamas over the next
several days. The low is anticipated to slowly move westward into
northwest Cuba by Wednesday night, and is forecast to bring
precipitation to both the Bahamas and Cuba late in the week. In
Hispaniola and Puerto Rico, most precipitation over the next few
days will be caused by local and diurnal effects, and is not
expected to exceed more than 25mm. The same will be true in the
Lesser Antilles and the Virgin Island until the end of the week,
at which point a tropical wave (AL95), currently located at 37W,
is forecast to bring in precipitation. The NHC has given it a 70%
chance of tropical cyclone development in the next seven days.


Tropical South America:

A long fetch of moisture with weak low-level flow and orographic
enhancement is expected to bring precipitation to the west coast
of Colombia. This moisture is not expected to be abnormal for the
season, and with weak flow in the lower level and a general lack
of upper-level support, precipitation totals will be seasonably
normal with the possibility of localized high precipitation
totals. A maximum of 20-45mm of precipitation is expected for this
area on Wednesday and Thursday Seasonably normal precipitation
will also be the case in the interior of tropical South America.
Seasonable but persistent moisture will move in from the Amazon
and will support daily localized convection throughout most of the
interior over the next few days.


Positions of Tropical/Easterly Waves Initialized at 12 UTC
TYP SOF INIT 06/00 06/12 07/00 07/12 08/00 08/12 09/00 09/12
TW  12N  36W   39W  42W   46W   48W  54W   Low ----------
TW  21N  49W   52W  54W   56W   58W  62W   Diss---------
EW  20N  62W   63W  64W   65W   Diss ------------

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

Blanco-Alcala...(WPC)
Rivera-Torres...(WPC)
$$