000 AXNT20 KNHC 131052 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 552 AM EST Wed Dec 13 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 0600 UTC surface analysis and satellite imagery through 1015 UTC. ...SPECIAL FEATURES... A cold front extends across the SW North Atlc from 32N72W SW to the Florida peninsula near Key Biscayne and into the southern Gulf of Mexico. Near gale to gale force winds are occurring generally N of 29N on either side of the front as depicted on earlier scatterometer passes from 13/0144 UTC and 13/0240 UTC. The front is forecast to sweep eastward through Wednesday and eventually lift N of the discussion area by Thursday. 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 06N10W to 06N15W. The Intertropical Convergence Zone axis extends from 06N15W to 03N40W to the Equator near 47W. Scattered moderate convection is from 03N-09N between 24W-54W. ...DISCUSSION... GULF OF MEXICO... The Special Features cold front mentioned above extends across the extreme southern Florida peninsula and into the basin near 25N81W extending W to 24N90W to 25N96W. A relatively dry and convection- free front...this reinforcing front is providing moderate to fresh N-NW winds E of 90W and gentle to moderate N winds W of 90W this morning. A surface ridge influences much of the remainder of the basin anchored by a 1026 mb high centered near Tampico and a 1025 mb high centered across southeastern Texas. As the cold front shifts eastward through Wednesday night...ridging will follow and provide light and variable winds on Wednesday. As the ridge continues east...the re-establishment of southerly return flow is anticipated Thursday. CARIBBEAN SEA... A stationary front extends from the Windward Passage SW to near 12N80W. Widely scattered showers and isolated tstms are occurring generally within 120 nm either side of the front. Much of this convection is supported aloft by a divergent upper level pattern on the northern periphery of an upper level anticyclone anchored over eastern Panama near 09N78W. East of the anticyclonic circulation...dry northerly flow prevails providing overall stability to the central and eastern Caribbean this morning. Overall gentle to occasional moderate trades are expected Wednesday E of the front...while the front is forecast to gradually weaken through Thursday. ...HISPANIOLA... Isolated showers are occurring across western portions of the island this morning as a stationary front lies from the Turks and Caicos through the Windward Passage to eastern Jamaica. The front is expected to remain stationary and begin weakening through Thursday. ATLANTIC OCEAN... Water vapor imagery indicates middle to upper level troughing moving offshore of the eastern CONUS this morning supporting the Special Features cold front extending from 32N72W SW to the southern Florida peninsula near Key Biscayne. The reinforcing cold front is expected to merge with a stationary front on Thursday that is currently analyzed to the E-SE from 32N65W to the Turks and Caicos islands to the Windward Passage region. The reinforcing cold front remains relatively convection-free...while isolated showers are occurring within 120 nm either side of the stationary front. Farther east...a surface ridge influences much of the central and eastern Atlc...anchored by a 1034 mb high centered S of the Azores near 37N28W. However...within the southeastern periphery of the ridge nearing the Cape Verde Islands...a dissipating cold front extends from the coast of Africa near 16N17W to 18N26W. The primary area of concern with the front is the large area of strong to near gale force NE winds generally N of 20N E of 33W. The pressure gradient associated with this wind field is expected to relax by Friday. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN