000 AXNT20 KNHC 092344 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 644 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 1800 UTC surface analysis and satellite imagery through 2330 UTC. ...SPECIAL FEATURES... A cold front extends across the Florida Straits from 25N80W across western Cuba into the Gulf of Honduras near 16N85W. Strong high pressure continues to build west of the front maintaining a strong pressure gradient and resulting in near gale northerly winds over the Yucatan Channel. These winds are forecast to diminish this evening. The front is forecast to extend from eastern Cuba to the southwest 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 06N20W. The Intertropical Convergence Zone extends from 06N20W to 00N50W. No significant convection is observed with these boundaries at this time. ...DISCUSSION... GULF OF MEXICO... The cold front described in the Special Features section is exiting the basin this evening, extending across the Florida Straits. Scattered moderate convection prevails along and within 210 nm east of the front. Surface ridging prevails across the Gulf waters anchored by a 1035 mb high centered over northeastern Mexico. Strong to near-gale northerly winds will continue across the Gulf, gradually diminishing through early Sunday. Thereafter, gentle to moderate north winds will prevail as high pressure builds in across the western waters early next week. CARIBBEAN SEA... Divergent mid 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 end of a strong cold front extends across western Cuba to 22N82W to the Gulf of Honduras near 16N85W and lies underneath this environment aloft, which is supporting scattered moderate convection along and within 210 nm east of the front. A pre frontal trough extends from 17N81W to 10N81W with scattered moderate convection. To the east, an elongated area of low pressure anchored by a 1010 mb low near 11N78W supports scattered showers south of 14N between 76W-80W. Fair weather prevails elsewhere. Near-gale force to frequent gusts winds are occurring west of the front over the Yucatan Channel. The front will continue to move east 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 Atlantic extends across the area. Scattered showers are forecast for the Windward Passage on 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 west Atlantic between a mid 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 1002 mb low centered off the coast of the Carolinas near 35N74W to 30N78W to near 25N80W. Scattered moderate convection is occurring generally within 210 nm east of the front. The remainder of the west Atlantic is under the influence of a surface ridge anchored by a 1026 mb high centered near 34N52W. In the central basin, a cut- off mid to upper-level low supports a 1015 mb low centered near 25N39W and associated trough extending from the low to 18N45W. Scattered moderate convection is occurring east of the low center from 20N-30N between 30W-38W. This low is forecast dissipate during the next 24 hours. Surface ridging also dominates the far eastern Atlantic, anchored by a 1032 mb high centered near 35N19W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA