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FXCA20 KWBC 111702
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
101 PM EDT Tue Mar 11 2025

Forecast Bulletin 11 March 2025 at 1710 UTC:

...Mexico and Central America...

On Tuesday, a progressive upper level pattern has established in
northern Mexico, where a fast moving upper trough is expected to
enter northwest Mexico Tuesday evening into Wednesday morning and
a frontal boundary in the lower levels is entering the region and
weakening over northwest Sonora by Tuesday evening. This system
will be progressing fast and dissipate over the southwest United
States by Wednesday. In north Honduras, a trough associated with
the remnants of a weak front over the north Caribbean will favor
moist conditions on Tuesday as it enters the region and interacts
with the terrain. On Wednesday, the region is dominated by a mid
to upper level ridge that extends into northern Mexico and over
Central America and west Caribbean. Generally dry conditions are
expected with isolated showers in the region as available moisture
remains low. By Thursday, another upper level trough extends into
northwest Mexico bringing with it cooler air and the potential for
snow in the higher elevations of Baja California. With the
increase in moisture expect more precipitation in north Baja
California on Thursday as it interacts with the terrain and has
upper level support from the divergence of the upper trough over
South California and Baja California. The rest of Central America
is expected to continue to see dry conditions as the upper ridge
meanders over the region. Limited totals of isolated precipitation
is expected. In terms of precipitation, on Tuesday, expect maxima
of 20-40mm in north Baja California and north Honduras. On
Wednesday, expect maxima of 10mm in El Salvador and dry conditions
in the rest of Central America and Mexico. On Thursday, with the
new frontal system, expect maxima of 20-35mm with a chance of
mountain snow in north Baja California and maxima of 15mm in south
Baja California and north Sonora. Isolated maxima of 10mm are
expected in the Golfo de Fonseca region and in south Costa Rica.

...Caribbean Basin...

An upper level trough is located over the West and the east
Caribbean Sea, favoring the presence of a frontal boundary that
extends from the Central Atlantic into south Bahamas, east Cuba
and weakening over south Cuba. Although with the cold front over
the north Caribbean, the amount of available moisture is low and
not conducive for heavy precipitation from Tuesday to Thursday. As
the upper trough continues to propagate eastward, so does the
frontal boundary into Hispaniola on Wednesday and becomes a weak
stationary front over Puerto Rico and Hispaniola by Thursday
evening. A weak prefrontal shear line develops east of the front,
where it is located over Puerto Rico on Wednesday and reaches the
central Lesser Antilles on Thursday. On Tuesday, expect maxima of
15-25mm in east Cuba and maxima of 10mm in south Bahamas, north
Hispaniola, and the central Lesser Antilles. On Wednesday, expect
maxima of 15-25mm in the Dominican Republic and maxima of 10mm in
south Hispaniola and Jamaica. On Thursday, expect maxima of
20-35mm in Hispaniola, maxima of 15-20mm in Puerto Rico and east
Dominican Republic, and maxima of 10mm in Jamaica and the central
Lesser Antilles.

...Tropical South America...

Low level troughs continue to propagate over tropical South
America and enhance the potential for convection over the region.
In the upper levels, the interaction between upper level systems
will enhance deep convection over the Amazon River Basin, where
the heavier precipitation is expected over the next three days.
Some lower level troughs are propagating northward into the
Guianas by Thursday evening, where heavy preciptiation is
expected. To the west, weak onshore flow will enter the western
coasts of Ecuador and Colombia, however the amount of available
moisture and the direction of the onshore flow will not favor
heavy precipitations, even with the upper level diffluence from
the easterly winds in the mid to upper levels. In terms of
precipitation, expect maxima of 25-50mm from south Venezuela to
east Amazonas-Brasil and west Para. Maxima of 20-40mm are expected
in west Colombia and north Suriname/French Guiana. The west Amazon
Basin can expect maxima of 15-30mm. On Wednesday, maxima of
25-50mm are expected in the eastern Amazon Basin and in the south
Guianas, while the north Guianas are expecting maxima of 20-35mm.
Maxima of 20-45mm are expected in Ecuador and north Peru, while
maxima of 20-35mm are expected in west Colombia. On Thursday,
expect maxima of 30-60mm from south Venezuela to Amazonas-Brasil,
while a maxima of 25-50mm are expected from northeast Venezuela to
north Guyana with a moist trough entering the region. Maxima of
20-40mm are expected from east Venezuela to north Para, while
similar amounts are anticipated in west Ecuador and north Amapa.
Expect maxima of 20-35mm in west Colombia.

For a graphical representation and details of the areas with
forecast rainfall:
https://www.wpc.ncep.noaa.gov/international/crb_day1-3.shtml

Castellanos...(WPC)

$$