Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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040 FXCA20 KWBC 061848 PMDCA Tropical Discussion - International Desks NWS Weather Prediction Center College Park MD 147 PM EST Thu Nov 06 2025 Forecast Bulletin 06 November 2025 at 1845 UTC: The Bahamas and the Caribbean: Dry air continues to persist over the eastern Caribbean, limiting rainfall activity across the area. Most of the precipitation for today is expected to happen over the Bahamas and portions of Cuba with moisture available in the area associated with a weakening stationary front. Additionally, enhancement in upper level speed divergence particularly over Central Bahamas associated with an upper level trough over the Gulf is expected. Precipitation may continue for the Bahamas from Friday through Sunday as upper-level speed divergence continues and some low-level troughs continue to enhance low-level moisture convergence in the area. Another region with the potential of some precipitation from today through Friday is Jamaica, with a low-level trough moving into the area and an increase in low-level moisture convergence. However, an upper level ridge over Honduras moving southeastward and extending over the Caribbean, could potentially inhibit the development of deep convection. The chances for rainfall and thunderstorms will increase from Friday through Saturday as an easterly wave advects moisture into the region in the afternoon and increases instability. This combined with diurnal heating and upper-level diffluence along the periphery of the upper level high may increase precipitation. Moisture associated with an easterly wave is expected to approach the Lesser Antilles from Friday through Saturday, increasing the precipitable water available in the area and increasing instability. Then from Saturday through Sunday precipitation should increase with the easterly wave over the islands, and upper level divergence increases with an upper level trough now south of Hispaniola, moving over the Leeward Islands enhancing deep convection and favoring the development of thunderstorms and periods of heavy rainfall. Mexico and Central America: For Mexico and Central America, most of the precipitation from today through Sunday will be due to low-level troughs, diurnal heating and local effects. Conditions are expected to remain relatively stable with dry air dominating over the region and limited support front mid- to upper-levels. An enhancement in precipitation may occur from today through Friday over the Yucatan Peninsula, as a low-level trough approaches the area and enhances moisture advection in the area and a mid-level trough further increases instability. Some upper-level support with a trough over the Gulf, although most of the upper level divergence is expected to stay offshore. Light rain may occur over Guatemala and El Salvador from Friday through Sunday with low- and mid-level troughs along the Pacific coast, although low precipitable water may limit precipitation. Over Nicaragua, moisture advection from the Caribbean is expected Saturday afternoon with an easterly wave reaching the region, and this combined with diurnal heating and local effects should increase precipitation. Costa Rica and Panama should expect to see some precipitation each day of the forecast period, due to the presence of the monsoon trough and moisture being advected from the Caribbean as a plume of moisture reaches the area today. Tropical South America: The presence of a plume of moisture over the Caribbean is expected to bring some precipitation from today through Friday over Colombia as low-level moisture convergence increases and upper level divergence is enhanced with upper level diffluence over the area. An area of interest from today through Friday is Venezuela, northern Brazil and Guyana. Thunderstorms and heavy precipitation is expected over the region as a plume of moisture associated with an easterly wave approaches the area, low-level moisture convergence is enhanced and upper level divergence increases along the periphery of an upper level high centered over northeastern Venezuela. Precipitation will continue over Venezuela from Friday through Saturday, as the easterly wave continues to propagate. From Saturday through Sunday a region of interest is the Pacific coast of Colombia, as onshore flow from the Pacific increases in the region. The rest of South America should expect some precipitation each day, mostly associated with low-level moisture convergence, moisture advection, diurnal heating and local effects Positions of Tropical/Easterly Waves Initialized at 12 UTC TYP SOF INIT 07/00 07/12 08/00 08/12 09/00 09/12 1/00 EW 14N 47W 49W 51W 53W 56W 58W 62W 64W EW 11N 56W 58W 60W 62W 64W 66W 68W 71W EW 14N 79W 80W 82W 84W ---------- For the latest available charts please visit: https://www.wpc.ncep.noaa.gov/international/crb_day1-3.shtml Rivera-Torres...(WPC) $$