Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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169 FXCA20 KWBC 131842 PMDCA Tropical Discussion - International Desks NWS Weather Prediction Center College Park MD 141 PM EST Thu Nov 13 2025 Forecast Bulletin 13 November 2025 at 1840 UTC: Mexico and Central America: Heavy precipitation due to a shear line and frontal system is expected to continue today through Saturday morning in Belize and Quintana Roo in Mexico. Strong low-level flow and ample precipitable water will continue to move onshore from the east into the evening hours on Friday, before dissipating overnight on Friday and into Saturday. Precipitation totals up to 40-80mm are still expected for this area on Friday, and 25-50mm is expected on Saturday. Remnant and reduced moisture will continue to make its way into the region on Saturday evening and Sunday bringing lighter precipitation. On Sunday night, moisture availability will further diminish and any remaining precipitation will be localized and light, most likely in the form of showers. In Baja California, a potent mid-latitude system, in the form of a cutoff low in the upper levels, will impact the northern portions of Baja California beginning Saturday, bringing precipitation from then until Monday. A cold front associated with the system will enter the coast from the Pacific, and with added low-level moisture convergence and strong upper-level divergence, heavy precipitation is expected, particularly on Saturday. A precipitation maximum of 20-45mm is expected on Saturday into Sunday. In Costa Rica and Panama, the presence of the monsoon trough and the Panamanian Low will promote a broad cyclonic circulation in the low levels, and onshore flow of moisture will continue to move from the Atlantic into the northern coasts of Costa Rica and Panama today through Saturday. By Sunday however, drier air is anticipated to intrude into the region, and precipitation will become much lighter and more localized. Localized heavy precipitation is still possible at higher elevations at this point due to orographic enhancement. On the Pacific side, a long fetch plume of moisture will remain in place through the forecast period. Much of the moisture in the low-levels will flow mostly parallel to the southern coasts, thus, precipitation will be in the form of heavy but localized convection. The Bahamas and Caribbean: A frontal system, which is currently bringing heavy precipitation to Belize and Quintana Roo in Mexico, will continue its slow southeastward progression through the Atlantic today and Friday. The cold front currently extends from the southern Bahamas, central Cuba, and the Caribbean Sea, just south of Cuba. Beginning on Friday, this front is expected to begin to dissipate, as a new cold front moves in and takes its place. Precipitation will occur along with the progression of the front in the central and southern Bahamas and the east coast of Cuba on Friday and Saturday, before moving into the island of Hispaniola on Sunday. Precipitation is expected to be light in most regions, with moderate amounts possible in isolated areas. Tropical South America: In northwest Brazil, a plume of moisture from the Amazon is expected to move westward towards southeast Colombia and northeast Peru on Saturday in the early morning hours. With the addition of low wind shear, but sufficient upper-level divergence, along with local and diurnal effects, heavy precipitation in the form of strong thunderstorms is expected on Saturday morning. In the west coast of Colombia, a long fetch plume of moisture associated with the presence of the monsoon trough will aid in the onshore flow of moisture from the west. Heavy precipitation for west Colombia is expected to occur today and Friday, with lingering but lighter precipitation on Saturday into Sunday. The highest precipitation totals are forecast to occur on the coast, where orographic ascent will be enhanced. In the interior portions of tropical South America, precipitation will be caused mostly by local, diurnal, and orographic effects, with daily convection expected in much of the north-central regions throughout the forecast period. Late over the weekend, a plume of drier air will move in from the east and intrude into north-central Brazil and the Guianas, and calmer conditions should be expected. Positions of Tropical/Easterly Waves Initialized at 12 UTC TYP SOF INIT 14/00 14/12 15/00 15/12 16/00 16/12 17/00 -- -- -- --- --- For the latest available charts please visit: https://www.wpc.ncep.noaa.gov/international/crb_day1-3.shtml Blanco-Alcala...(WPC) $$