Tropical Weather Discussion

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Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Wed Dec 6 2023 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1040 UTC. ...SPECIAL FEATURES... Western and Central Atlantic Gale Warning: A cold front extends from a 1004 mb low pressure near 35N72W to 31N72W to the northwest Bahamas to the Straits of Florida. Fresh to strong NW winds have developed west of the front and north of 28N, and seas have recently built to about 7 ft. As the low deepens and moves eastward across the western Atlantic, it will channel near-gale to gale W to NW winds behind the front north of 28N between 69W and 75W by early this afternoon. Seas in this area will build to between 11 and 13 ft. These winds are going to shift eastward across the western Atlantic into the central Atlantic tonight through Thursday. Seas will build further to between 14 and 18 ft. Please read the latest High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic through the coast of Africa near 11N15W to 05N20W. The ITCZ continues westward from 05N20W to 04N35W to 07N48W. Scattered moderate convection is seen south of the trough from 01N to 07N between 05W and 18W. Scattered moderate convection is also present from 02N to 12N between 33W and 52W. ...GULF OF MEXICO... As of 0900 UTC, the cold front is over the Yucatan Channel and is exiting the Gulf of Mexico. However, a sharp surface trough still exists in the west-central Bay of Campeche, offshore of Veracruz, inducing strong winds and 6 to 7 ft seas from 18.5N to 22N between 92W and 96.5W. In the NE Gulf of Mexico, fresh to strong NW to N winds and seas 5 to 6 ft are occurring north of 27N and east of 88.5W. Elsewhere, moderate to fresh N to NE winds prevail with 3 to 5 ft seas. Cloudiness along with isolated to scattered light showers prevail over portions of the central and southwest Gulf. For the forecast, fresh to strong northerly winds are expected to persist along the coast near Veracruz, Mexico through today. Strong NE winds will expand across the Bay of Campeche this afternoon before diminishing tonight. High pressure behind the front will shift E into the Atlantic Thu night, inducing moderate to fresh return flow across most of the basin Fri through Sat, ahead of the next cold front that is forecast to enter the NW Gulf Sat evening. Strong to near-gale force winds are likely behind the front, with gale force winds possible in the SW Gulf. ...CARIBBEAN SEA... Water vapor satellite imagery at low to mid levels indicate a very dry trade-wind pattern over much of the basin. Nevertheless, convergent trade winds are causing isolated showers between 15N and 18N across much of the basin. Strong NE to E trade winds prevail over the south-central Caribbean, locally near-gale force near the coast of Colombia. Fresh trades prevail elsewhere across the eastern and central Caribbean, with mainly moderate NE winds in the NW Caribbean. The exception is in the Yucatan Channel, where an arriving cold front is inducing fresh NE winds. Seas are 8-10 ft in the south-central basin, and 5-7 ft elsewhere in the eastern and central Caribbean. Seas are 3 to 5 ft in the northwestern basin. For the forecast, large NE swell is expected to continue across the Tropical N Atlantic waters to the east of the Lesser Antilles through Thu. The cold front currently in the Yucatan Channel will reach from the N coast of Hispaniola to the Gulf of Honduras Thu night, where it will remain nearly stationary through Sat. Fresh to strong NE winds are expected to develop in the vicinity of the front across the Yucatan Channel and in the lee of Cuba tonight. Strong winds will develop in the Windward Passage Thu evening with the front and expand across most of the east and central Caribbean by Sat. ...ATLANTIC OCEAN... Please see the Special Features section about a Gale Warning in the Atlantic. Besides the cold front and related seas and weather mentioned in the Special Features section, another cold front extends southwestward from the north-central Atlantic across 31N57W to 30N63W, then continues as a warm front to 31N66W, and eventually connects to the 1004 mb low pressure near 35N72W. Scattered showers are evident north of 29N between 35W and 52W. A 1022 mb high pressure centered near 27N44W extends a surface ridge west- southwestward toward the southeastern Bahamas. The ridge dominates much of the basin from 19N to 27N, with gentle winds and 4 to 6 ft seas. Fresh SW winds and 7 to 9 ft seas are occurring north of the surface high pressure center, and south of the aforementioned front, mainly north of 29N between 43W and 54W. In the eastern Atlantic, another cold front stretches southwestward from a 1011 mb low south of Portugal across 31N11W through the Canary Islands 27N20.5W, then continues as a stationary front to 25N28W. Scattered showers and isolated tstorms are noted within 90 nm of this boundary, aided by an upper-level low in the vicinity. Strong upper-level flow is carrying thick cirrus from this convection northeastward across the Cabo Verde Islands to near the Canary Islands. In the tropical latitudes, between Africa and the Lesser Antilles, fresh to locally strong trade winds and 8 to 9 ft seas prevail from 05N to 17N between 33W and the Lesser Antilles. For the forecast W of 55W, the cold front extending from 31N72W to the Straits of Florida will move SE and reach from near 31N63W to eastern Cuba by this evening, then weaken from near 31N48W to the N coast of Hispaniola Thu evening. Gale-force winds and high seas are expected both ahead of and behind this front, to the north of 28N, and east of 75W, this afternoon through Thu evening. The front will stall along 20N Fri through Sat as strong high pressure builds across the western Atlantic.