000 AXNT20 KNHC 061801 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 101 PM EST Wed Dec 6 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... ...GALE-FORCE WINDS IN THE GULF OF MEXICO... A cold front extends from St. George Island Florida SW to 27N90W where it transitions to a warm front that connects to a 1015 mb low near 26N95W. Another cold front extend from the low SW to Tampico, Mexico. Frequent gust to gale force winds are north of the front with seas reaching to 9 ft. Strong to gale force northerly winds and rough seas are expected in the wake of the front as it moves across the basin through Saturday morning. Latest model guidance indicates reinforcing cold air, with gale force winds over the west-central gulf on Thu, and over the SW gulf by Thu night. 12 ft seas are likely to occur in the central and western Gulf Thu through late Fri night, with a peak close to 18 ft in the SW Gulf. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. ...ITCZ/MONSOON TROUGH... The Intertropical Convergence Zone axis extends from 08N13W to 05N30W to 04N50W. Scattered moderate convection is from 01N to 08N E of 43W. ...DISCUSSION... GULF OF MEXICO... A broad middle to upper level trough over the eastern CONUS continue to support a cold front that at 1500 UTC extends from St. George Island Florida SW to 27N90W. From that point it transitions to a warm front that connects to a 1015 mb low near 26N95W. Another cold front extend from the low SW to Tampico, Mexico. Frequent gust to gale force winds are north of the front with seas reaching to 9 ft. Isolated showers are within 165 nm N and W of the front and within 90 nm E of it. A weak surface trough is in the Bay of Campeche extending from 22N93W to 17N94W with isolated showers within 75 nm either side of its axis. Deep layer dry air support fair weather elsewhere ahead of the front. The front is forecast to move ESE and exit South Florida Saturday morning. Heavy showers are expected in the SE Gulf Friday into Saturday as the front moves off the basin. For further details see special features. CARIBBEAN SEA... Deep moisture over the SW Caribbean is interacting with diffluent flow aloft and support a cluster of moderate to isolated strong convection from 11N to 14N W of 80W. Isolated showers are elsewhere in the SW basin being supported by the eastern extension of the EPAC monsoon trough. The tail of a cold front over the central Atlc waters is fast approaching the NE Caribbean and will support showers and tstms through Friday night, including Puerto Rico, the Virgin Islands and the Leeward Islands. The remainder of the Caribbean is generally void of convection. High pressure north of the region supports fresh to near gale-force winds over the Central Caribbean being the strongest winds along the coast of Colombia. Heavy showers are expected to develop Friday night over the NW Caribbean associated with a cold front entering the region Saturday morning. ...HISPANIOLA... Deep layer dry air in the region supports fair weather through this evening. Showers are forecast to develop tonight mainly across the eastern half of the Island associated with the tail of a cold front over the central Atlc waters. This shower activity is expected to continue through early Friday morning. ATLANTIC OCEAN... Strong ridging prevails over SW N Atlc waters being anchored by a 1026 mb high near 33N63W. A cold front associated with a vigorous low pressure system N of the area extends along 30N38W SW to 20N50W to 21N62W. Diffluence aloft support scattered moderate convection within 210 nm E of the front N of 23N. A reinforcing cold front extends from a 1011 mb low near 30N45W SW to 26N46W to 25N51W. There is no convection associated with this boundary at this time. Fresh to near gale-force winds are N of 27N E of the front to 35W and W of the front to 55W. A weak pre-frontal trough extends from 21N34W to 15N37W with no convection. High pressure centered over Spain extends SW and covers the remainder of the eastern Atlantic. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos