Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
1228 PM EDT Fri Mar 14 2025

Forecast Bulletin 14 March 2025 at 1630 UTC:

...Caribbean Basin...

On Friday, an upper level trough in the central Atlantic Ocean
extends into the eastern Caribbean Sea and is expected to quickly
propagate eastward further into the central Atlantic by Saturday.
This upper level system is favoring the presence of a frontal
boundary over the Greater Antilles, which is expected to remain
stationary over the next three days and weaken by Sunday evening.
As the upper trough moves away from the region, the subtropical
ridge enhances over the region by early Sunday morning, until it
interacts with a second trough with its base over portions of
western Cuba by early Monday morning. The frontal boundary favors
the heaviest precipitation on Friday and begins decreasing over
the weekend as the available moisture is highest on Friday and
decreases over the weekend over the Greater Antilles. Over the
Lesser Antilles, the pattern of moist plumes entering the region
through the easterly trades are expected on Friday and Saturday.
On Sunday, a trough is expected to develop over the Lesser
Antilles while a circulation in the upper level develops in the
open ocean waters of the Central Atlantic on Sunday, with a weak
cold frontal boundary east and north of the eastern Caribbean.
Precipitation values are not expected to be large due to the
presence of low available moisture in the region. On Friday,
expect maxima of 25-50mm in Puerto Rico/VI as the amount of
available moisture remains high in the region. The Dominican
Republic can expect maxima of 15-30mm while south Haiti and
Jamaica can expect maxima of 15-20mm. On Saturday, expect maxima
below 15mm in the Windward Islands, Puerto Rico, and south Haiti.
On Sunday, expect maxima of 15-20mm in the Lesser Antilles, and
maxima below 15mm in Jamaica, south Haiti, and from Puerto Rico
through the north Leeward Islands.

...Mexico and Central America...

Over the next three days, the regions of Mexico and Central
America are expected to be primarily dry as the upper level ridge
dominates the majority of the region. This subtropical ridge
extends over Central America and reaches central Mexico on Friday.
On Saturday and Sunday, the ridge begins to interact with a potent
upper level trough that is pushing south from the United States
into north Mexico by Saturday and reaches the Yucatan Peninsula by
early Monday. By Sunday into Monday, southern Mexico is expected
to see the propagation of a strong cold front that interacts with
the terrain, favoring orographic lift along the eastern Sierra
Madre del Sur. Moderate precipitation is also expected in central
Guatemala due to the development of a prefrontal trough that
extends over the Yucatan Peninsula into central Guatemala.
Elsewhere in Central America, more available moisture is expected
in western regions of Costa Rica and Panama, as well as El
Salvador, but significant precipitation values are not expected
over the next three days. On Friday, expect maxima below 15mm in
north Baja California and El Salvador. On Saturday, Costa Rica can
expect maxima of 15mm. On Sunday, expect maxima of 20-45mm in
central Guatemala, and maxima of 20-35mm in Chiapas. Maxima of
15-25mm are expected from the central Yucatan through north
Guatemala. From south Costa Rica to west Panama expect maxima of
15mm.

...Tropical South America...

Over the next three days, the northern regions of South America
will be under the periphery of two upper level ridges that will
interact, enhancing the ventilation for deep convection. The
Bolivian High in the south is expected to strengthen over central
regions of South America, while the subtropical ridge over Central
America and the Caribbean meanders over the region over the
weekend. The areas of interest on Friday and Saturday include the
regions of Amazonas-Brasil, north Peru into southern Colombia, and
western regions of Ecuador and Colombia. On Sunday, the areas of
interest are western Colombia and Ecuador as the interaction of
the upper level ridges will favor diffluence over the region and
enhance deep convection. Additionally, moist onshore flow will be
from the west and south, providing the moisture for precipitation.
In terms of precipitation, on Friday, expect maxima of 25-50mm
from south Venezuela/west Colombia into north Amazonas-Brasil. And
maxima of 30-60mm from southwest Colombia to west Ecuador.
Generalized maxima of 20-45mm are expected from south Colombia
into north Peru and over the Guianas. Central portions of Colombia
can expect maxima of 15-30mm. On Saturday, expect maxima of
35-70mm in west Ecuador and in the central Amazon Basin. Maxima of
25-50mm are expected from south Colombia into the western Amazon
Basin. North Colombia can expect maxima of 20-40mm, while maxima
of 15-30mm are expected in the Guianas and portions of the Amazon
Delta, as well as central Venezuela. By Sunday, expect maxima of
40-80mm in west Ecuador, and maxima of 30-60mm in west Colombia
and over regions of south Guyana into north Para-Brasil. From
south Venezuela into Amazonas-Brasil and north Peru expect maxima
of 20-45mm. From the Guianas to Amapa expect maxima of 20-35mm.

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)