000 AXNT20 KNHC 071744 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1244 PM EST Sun Jan 7 2018 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... ...Atlantic Gale Warning... Strong high pressure of 1040 mb building SE toward the U.S. Atlantic coast supports strong to gale-force northeast winds mainly south of 25N and west of a stationary front that currently extends from 31N55W to 25N65W to 20N73W. Gale force winds will also develop across the Windward Passage overnight. Seas are forecast to build to 10-13 ft within the area of gale-force winds. Fresh to strong NE winds are expected to also affect the remainder of the waters between the Bahamas and Cuba, and the Straits of Florida with seas up to 12 ft outside the Bahamas. Conditions across the region will improve Mon night as the high shifts east and weakens and the front dissipates. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...Caribbean Gale Warning... The aforementioned high pressure is also currently bringing strong to gale-force northeasterly winds in the lee of east- central Cuba, including the Cayman Islands as indicated by a recent scatterometer pass. These conditions will continue through this afternoon. Gale winds will then become confined to the Windward Passage and approaches to the passage north of 16N and west of the stationary front to 76W by tonight. Seas are forecast to build to 10-12 ft near the Cayman Islands. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean from the Africa coast near 08N13W and continues to 03N23W. The Intertropical Convergence Zone extends from 03N23W to 00N42W. Scattered showers are within 120 nm on either side of the ITCZ between 26W-42W. ...DISCUSSION... GULF OF MEXICO... A ridge dominates the basin anchored by a strong high pressure of 1040 mb located near 37N78W. To the southwest, a surface trough extends from 26N93W to 23N92W. The pressure gradient between the high pressure to the north and lower pressures over the Caribbean support fresh to strong easterly winds over the Straits of Florida and eastern half of the basin. Mainly moderate to fresh easterly winds prevail elsewhere. Expect for the next cold front to emerge off the Texas and Louisiana coasts on Monday, followed by mainly fresh northerly winds and building seas of 5-6 ft. The front and associated winds will weaken on Tuesday. CARIBBEAN SEA... A stationary front extends across the Windward Passage near 20N75W to 12N81W. Clusters of moderate convection are noted along the the frontal boundary mainly north of Jamaica. Latest scatterometer data indicated that strong to gale-force winds are now occurring over the Lee of Cuba, while fresh to strong winds are occurring across the Windward Passage and the south-central Caribbean near the coast of Colombia. The stationary front will slowly weaken during the next few days. Strong high pressure building southeast toward the U.S. Atlantic coast will continue supporting the gale- force winds between Jamaica, the lee of Cuba and the Windward Passage and approaches. Please see the Special Features section for more details. ...HISPANIOLA... The region is between a stationary front through the Windward Passage and a surface trough approaching from the southeast. The moisture from these two features will support showers and thunderstorms over the island through Monday. High pressure building to the north will support 20 to 30 kt NE winds over the northern coast of Haiti this afternoon and tonight. ATLANTIC OCEAN... A stationary front enters the area of discussion near 31N55W and extends to 20N73W. Scattered moderate convection is noted within 390 nm west of the front. The pressure gradient between strong high pressure over eastern U.S. and the stationary front supports 20 to 30 kt NE winds and seas of 7 to 10 ft in unprotected waters south of 25N and west of the front. To the east, a 1031 mb surface high centered near 32N36W supports a broad area of fresh to strong easterly trades south of 23N over the central and eastern Atlantic. The combination of these winds and a northwest swell from a departing storm system over the northern Atlantic supports seas of 8 to 14 ft over the majority of the Atlantic discussion waters between the Cabo Verde Islands and 75W. Higher seas of 12 to 18 ft are occurring N of the Cabo Verde Islands under strong northerly winds on the eastern periphery of the Atlantic high pressure. The surface high over eastern U.S. will shift east through tonight and will increase the pressure gradient just west of the stationary front. This will result in gale-force winds developing over the Windward Passage and approaches later. Please refer to the Special Features section for more details. For additional information please visit http://www.hurricanes.gov/marine $$ ERA