000 AXNT20 KNHC 091803 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 103 PM EST Sat Dec 9 2017 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... A cold front extends across the Florida Straits from 25N80W SW to 23N82W then across western Cuba into the Gulf of Honduras near 16N86W. Strong high pressure continues to build-in west of the front maintaining a strong pressure gradient and resulting in near gale to gale force NW to N winds generally S of 24N W of the front to 91W. These winds in the Gulf of Mexico are forecast to diminish below gale-force this afternoon. Near gale NW winds with frequent gusts are occurring in the NW Caribbean west of the front along with 10 ft seas. The front is forecast to extend from eastern Cuba to the SW Caribbean waters on Sunday morning, leading to gale force winds in the offshore waters of Nicaragua and Honduras. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 07N13W to 05N19W. The Intertropical Convergence Zone axis extends from 05N19W to 03N36W to 02N51W. Scattered moderate convection is from 01N to 06N between the prime meridian and 18W. ...DISCUSSION... GULF OF MEXICO... The main feature across the basin is the Special Features cold front extending across the Florida Straits. Aside from the near gale to gale force winds, scattered showers are occurring ahead of the front, including the South Florida peninsula. Isolated showers are in the Yucatan channel. The cold front is forecast to move off the SE basin later this afternoon and winds are expected to diminish below gale-force. However, strong to near gale NW winds will continue across the E and SW Gulf...gradually diminishing from the NW to SE through early Sunday. Thereafter, gentle to moderate N winds will prevail as high pressure builds in across the western waters early next week. CARIBBEAN SEA... Divergent middle to upper level flow is noted over the western Caribbean between the upper level trough over the Gulf of Mexico and an upper level anticyclone centered over northern Colombia. The tail of a strong cold front extends across western Cuba to 22N82W to 20N85W to the Gulf of Honduras near 16N86W and lies underneath this environment aloft, which is supporting scattered showers and tstms N of 18N ahead of the front to 76W. In the SW basin, an elongated area of low pressure anchored by a 1010 mb low near 11N78W support similar convection S of 17N W of 75W. Near gale force to frequent gusts winds are occurring W of the front. The front will continue to move SE and is forecast to extend from eastern Cuba to the SW Caribbean by Sunday morning. Gale force winds will be on Nicaragua and Honduras adjacent waters. Heavy showers with potential for flooding and mudslides are forecast for Costa Rica and Panama. The front is forecast to stall across the western Caribbean Sunday night through Tuesday and gradually weaken by mid-week. The trades will weaken gradually across the eastern Caribbean by Sunday as a ridge N of the area weakens and retreats northward. ...HISPANIOLA... Fair weather conditions prevail across the island as a surface high centered in the central Atlc extends ridging across the area. Scattered showers are forecast for the Windward Passage Sunday to early next week associated with a cold front moving across Cuba and the W Caribbean. ATLANTIC OCEAN... Southwesterly flow aloft is noted on water vapor imagery over the SW North Atlc between a middle to upper level trough over the eastern CONUS and Gulf of Mexico and an upper level ridge anchored over the central Caribbean Sea. The trough supports the Special Features cold front which extends from a 1005 mb low centered off the coast of the Carolinas near 33N76W to 30N78W to South Florida near 25N80W. Scattered showers and tstms are occurring generally within 210 nm E of the front as the entire system moves rapidly off to the NE. Otherwise, the remainder of the SW North Atlc waters is under the influence of a surface ridge anchored by a 1027 mb high centered near 32N53W. In the central basin, a cut- off middle to upper level low supports a 1015 mb low centered near 25N38W and associated trough extending from the low to 24N35W to 18N43W. Scattered showers and tstms are occurring E of the low center from 20N to 29N between 28W and 34W. The low is forecast to gradually weaken through tonight and then drift westward as a surface trough across the central Atlc through Monday. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos