


Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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105 FXCA20 KWBC 071940 PMDCA Tropical Discussion - International Desks NWS Weather Prediction Center College Park MD 340 PM EDT Tue Oct 07 2025 Forecast Bulletin 7 October 2025 at 1930 UTC: The Bahamas and the Caribbean: Today into Wednesday some precipitation should be expected on the Lesser Antilles with moisture advection. Over Puerto Rico thunderstorms are likely to occur with the presence of an upper-level trough and the instability associated with an induced trough over the area. Over Cuba and Bahamas, some precipitation should be expected as there is moisture and a low-level circulation bringing flow onshore. For the rest of the Caribbean seasonable precipitation due to local effect and diurnal heating are likely. From Wednesday to Thursday relatively calm conditions, and with the upper level trough weakening over Hispaniola precipitation in the Caribbean will most likely be due to local effects and diurnal heating. A low-level circulation remains over Cuba, bringing some instability and increasing chances of precipitation. More convective activity and unstable conditions are expected towards the end of the forecast period. From Thursday into Friday, an upper-level trough moves over eastern US extending into southeast US, moving its divergent side approaching the Bahamas and western Cuba. Precipitable water increases over the region with a stationary front, and a low-level trough from Bahamas into Cuba increases instability in the region, convective activity and period of heavy rainfall can be expected. Tropical Storm Jerry may approach the region enhancing rainfall, particularly over the Leeward Islands on Friday. With the enhancement of moisture associated with the storm, local effects and diurnal heating some precipitation should also be expected for the rest of the Lesser Antilles and Puerto Rico by the end of the workweek into the weekend. Mexico and Central America: Hurricane Priscilla continues to cause some precipitation particularly over Baja California Sur today into Wednesday, and will continue to bring moisture and produce heavy rainfall over portions of west-central Mexico today into Thursday. The impact of the tropical cyclone over Mexico, in terms of precipitation, diminishes gradually over the forecast period A developing low-level circulation, currently being monitored by the National Hurricane Center (NHC) with a 80% chance of development in the next seven days, will bring precipitation to portions of Central America and the Pacific coast of Mexico from today into Friday, as it continues to move along the Pacific coast. The low-level circulation has mid- and upper-level support with the presence of a trough, and heavy rainfall is expected each day, with maximum accumulation around 25-50mm and higher values locally each day. An upper level trough with an associated low-level induced trough in the Bay of Campeche is expected to continue to bring heavy rainfall in the region. The divergence associated with the upper level trough over the Yucatan Peninsula and significant moist low-level flow will aid in promoting precipitation today into Wednesday and in portions of Tabasco, Campeche and Veracruz. There is also a low-level trough over eastern Yucatan and Belize that is being supported with divergence from the upper level trough in the Bay of Campeche that will enhance precipitation in the eastern portion of Yucatan today into Wednesday. From Wednesday to Thursday very significant precipitation is expected over Veracruz, east San Luis Potos and south Tamaulipas with the retrograding upper level trough and the low-level trough over the Campeche Bay will produce strong and moist onshore flow from the east-northeast. This along with orographic enhancement will be conducive to heavy precipitation. As the low-level trough moves inland, low-level moisture convergence is expected to continue enhancing rainfall from Thursday to Friday. Heavy precipitation is expected for Costa Rica from Wednesday into Friday, with the presence of the monsoon trough and a low enhancing circulation in the region that will favor moist onshore increase. In addition, a developing upper-level trough will enhance upper level divergence over Costa Rica particularly from Thursday into Friday, increasing the instability and convective activity into the region. Tropical South America: Over the tropical South America, precipitation will be mostly due to moisture advection, diurnal heating and local effects for the forecast period. Some convective activity and thunderstorms will likely happen over the Amazon region from today into Wednesday as there is some support from mid and upper level shortwave troughs. A long fetch of moisture with weak low-level flow and orographic enhancement is expected to bring precipitation to the west coast of Colombia from Wednesday into Friday. Positions of Tropical/Easterly Waves Initialized at 12 UTC TYP SOF INIT 08/00 08/12 09/00 09/12 10/00 10/12 11/00 11/12 TW 16N 54W 56W 58W 60W Diss---------- For the latest available charts please visit: https://www.wpc.ncep.noaa.gov/international/crb_day1-3.shtml Rivera-Torres...(WPC) Blanco-Alcala...(WPC) $$