Tropical Discussion - International Desks
NWS Weather Prediction Center College Park MD
1248 PM EST Wed Feb 19 2025

Forecast Bulletin 19 February 2025 AT 1930 UTC

The large scale conditions show a disorganized upper divergent
phase of the Madden-Julian Oscillation crossing the Americas.
Although the signal is disorganized, there are still areas where
enhanced ventilation is highlighting ascent and precipitation in
combination with synoptic systems. One of them is Mexico and
another northwest South America and southern Central America.

North in the domain...a surface front is propagating southward in
association with cyclogenesis occurring in the southeast USA. By
Wednesday evening expect the front to extend across central
Florida, the central Gulf, southern Veracruz and along the sierra
madre oriental in Mexico into southwest Coahuila. By Thursday
evening the front is forecast across the northwest Bahamas,
northwest Cuba, the northern Yucatan Peninsula and into the
Tehuantepec Pass. In areas west expect a stationary boundary
across the Sierra Madre Oriental into southwest Coahuila. By
Friday evening expect a cold front across the southeast Bahamas, a
stationary boundary across central Cuba and into the northwest
Yucatan Peninsula. Expect a Tehuantepecer LLJ to develop on
Thursday, forecast to reach speeds over 40kt. In terms of
precipitation, expect the largest amounts clustering in areas
west, to include a risk for Thunderstorms given enhanced upper
divergence and high values of moisture and instability. Through
early Thursday, expect the heaviest precipitation in
Tabasco/Chiapas and southern Veracruz where onshore flow and
terrain enhancement will favor maxima of 25 - 50mm, while in
northern Guatemala and Campeche/southeast Chiapas expect maxima of
20 - 45mm. In the northwest Yucatan Peninsula expect maxima of 15
- 25mm. Similar amounts are expected in northern slopes of
southern and northern Veracruz. On Thursday expect a peak in
terrain enhancement in southern Veracruz/Tabasco/Chiapas, where
amounts are forecast to reach 20 - 40mm/day and isolated maxima of
75 - 125mm. Scattered thunderstorms will favor maxima of 15 - 25mm
in most of the Yucatan Peninsula, Campeche and northern Guatemala.
Lesser accumulations are expected thereafter. Frontal
precipitation amounts in Cuba and areas to the east will favor
much lighter accumulation.

In southern and central Mexico, including the Eje Volcanico
Transversal Central, expect wetter conditions for this time of the
year to persist into the weekend given enhanced availability of
moisture and a persistent upper divergent pattern. This will favor
scattered showers and a very isolated thunderstorm on
Friday...where amounts of 05 - 10mm/day and maxima of 15mm are
forecast.

The eastern Caribbean will be under the influence of a mid-level
ridge, forecast to center well to the northeast of the Leeward
Islands through the cycle while extending its stabilizing
influence and associated dry air into most of the central and
eastern Caribbean. This will continue to favor seasonally
conservative rainfall accumulations. Wetter conditions are
expected in southern Central America and northwest Colombia where
enhanced upper divergence in the southwestern periphery of a cell
of the subequatorial upper ridge continues to favor scattered
thunderstorms while interacting with an unseasonably warm and
moist air mass. This will favor maxima of 20 - 35mm through early
Thursday, maxima of 15 - 20mm by Thursday into early Friday and
maxima back into the 20 - 35mm/Day range on Friday through early
Saturday, particularly for the Bocas del Toro region.

A region of interest is Ecuador and far southwest Colombia, where
warm SST and the Pacific ITCZ are stimulating diurnal convection
in the Pacific basins. Through early Thursday expect maxima of 25
- 50mm in northwest Ecuador/southwest Colombia, while elsewhere in
the Ecuadorian coast expect maxima of 20 - 45mm. On Thursday
through early Friday expect maxima of 25 - 50mm in most of the
Ecuadorian coast. On Friday through early Saturday expect maxima
of 30 - 60mm as the low-level flow and precipitable water content
become more favorable for heavy precipitation.

Galvez...(WPC)