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FXCA20 KWBC 112009
PMDCA

Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
308 PM EST Tue Feb 11 2025

Forecast Bulletin 11 February 2025 AT 2000 UTC

There hasn`t been major changes in the overall synoptic pattern or
short term forecast from the previous discussion. That said, an
exception is that by Thursday night into Friday morning, a cold
front is forecast to move south into northeastern Mexico. An
increase in moisture will be observed over the Veracruz region and
nearby Mexican states, which will increase the chances of showers,
with up to 45mm of rain across isolated areas. Shifting the
attention to northern South America, the main areas with
significant rainfall over the next three days are expected to be
across its tropical region, in particular along the west coast of
Ecuador and Colombia. The west coast of Ecuador and Colombia will
have an influx of moisture over the next few days, while there is
also divergence aloft, which could cause daily thunderstorms over
the area. That being said, the moisture is not as deep as it was
observed yesterday, and even though the precipitable water will be
in the range of 52-57mm, the model guidance suggests that the
moisture will be near, to slightly below normal over the eastern
Pacific just offshore of the Ecuador and Colombia coasts.
Therefore, even though daily showers and thunderstorms are
forecast, it is expected to produce lower accumulations compared
to yesterday. From today into Friday morning, daily rainfall
maxima is forecast to be in the order of 25-50mm each day across
the area. The Caribbean region will remain relatively dry, but
brief shower activity is expected across the area and into the
windward side of Central America. The brief shower activity is
expected to cause modest rainfall accumulations, with some areas
possibly observing as much as 10-20mm on any given day, but most
areas are expected to observe lighter and isolated shower
activity.

A ridge of high pressure is located over the Caribbean in the mid
and upper levels, which will dominate the Caribbean region into
the western Tropical Atlantic. This will continue to keep the area
under a fairly stable atmosphere, allowing only some shallow
convection across isolated areas. There is also dry air in the mid
levels moving over the Caribbean region that will persist for the
next few days. The 700 hpa RH values are below normal across most
areas in the Caribbean and into the Gulf, but an even more
widespread presence of dry air can be observed at the 500 hpa
level, suggesting that the available moisture is mainly limited to
the lower levels. The patches of moisture in the lower levels are
associated with low level shortwave troughs moving through the
Caribbean. Across tropical South America the mid and upper levels
will continue to cause divergence across western Colombia and
Ecuador, while areas from Peru to Brasil will have very light
winds aloft and some diffluence, allowing for isolated deep
convection, but otherwise convection will be mainly diurnally and
locally induced.

At the surface, there is a high pressure that continues to
dominate the tropical region, mainly across the Caribbean and the
Tropical Atlantic. A surface high pressure center is expected to
center across the central Atlantic by Wednesday afternoon into
Thursday. A weak surface low pressure will develop over the east
coast of Mexico on Wednesday night into Thursday, but it will move
away and a high pressure will move into eastern Mexico by Friday.
The low level winds are still expected to be relatively strong for
the next several days across the Caribbean, Tropical Atlantic and
into the Gulf. The latest model guidance insists that the 850 hpa
winds will surpass 25 KT over much of the Tropical region,
especially over the waters. These strong winds will also
contribute to the brief nature of the shower activity, as any
shower that may develop will move quickly over any one area.

In terms of rainfall, as mentioned above, the Caribbean region
will have minimal to modest amounts of over the next few days,
while western Ecuador and Colombia will have significant rainfall
each day this week. Mexico is expected to have a dry today and on
Wednesday, with essentially fair weather across the country.
However, an increase in moisture across eastern Mexico will cause
an increase in shower activity, up to 45mm from Thursday into
Friday morning over areas in and around Veracruz. Once again, the
area with the best chance of significant rainfall is the tropical
region of South America. The Guianas and Amapa of Brasil are
expected to observe showers and thunderstorms as low level
moisture moves in with the trade winds and the proximity to the
ITCZ, with rainfall maxima near 20-35mm today and on Thursday, but
up to 45mm is possible on Wednesday. Dry air will move in over
Venezuela into northeastern Colombia with the nocturnal LLJ
bringing dry air each day. Other areas across northern South
America, including northern Peru, and across Brasil including the
Amazonas and Para will have diurnal convection, with daily maxima
ranging between 20-50mm today and Thursday, and up to 35mm on
Wednesday.



Alamo...(WPC























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