000 AXNT20 KNHC 061157 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 657 AM 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...SPECIAL FEATURES... ...GALE-FORCE WINDS IN THE GULF OF MEXICO... A cold front passes through the Florida Panhandle, into the N central Gulf of Mexico, to the coast of the Deep South of Texas, and then inland near 23N99W in Mexico, and northwestward. Expect frequent gusts to gale-force, and sea heights to 9 feet, to the NW of the cold front, until this afternoon/early this evening. The gale-force wind conditions will last for the next 12 hours or so, and then change to less than gale-force wind speeds. The cold front will continue to move toward the E and SE, through the Gulf of Mexico. The cold front position for Thursday afternoon will be approximately along 27N83W 26N89W 23N94W 18N93W. Expect gale- force NW-to-N winds, and sea heights from 9 feet to 13 feet, from 21N to 24N W of 96W. Please read the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through the coastal sections of Sierra Leone near 07N12W, until 07N13W. The ITCZ continues from 07N13W to 06N20W, 05N30W, 05N44W, and 05N48W. Precipitation: widely scattered moderate to isolated strong rainshowers are from 02N to 08N between 13W and 42W. Isolated moderate elsewhere from 01N to 08N between 42W and 57W. ...DISCUSSION... THE GULF OF MEXICO... Middle level-to-upper level westerly wind flow and comparatively- drier air in subsidence cover the Gulf of Mexico to the east of the line from : NE Florida, into the central Gulf of Mexico, into the SW corner of the Gulf of Mexico near 20N97W. A middle level to upper level trough is in the E and SE Gulf of Mexico, and into the Yucatan Channel. A cold front passes through the Florida Panhandle near 31N85W, to 28N90W in the north central Gulf of Mexico, to the coastal border of Texas and NE Mexico, inland near 23N99W in Mexico, curving northwestward to 28N102W. Upper level W-to-NW wind flow is to the west of the cold front. Low level clouds and rain are along the frontal boundary. A surface ridge passes through central Florida, into the central Gulf of Mexico, and finally into the W part of the Isthmus of Tehuantepec of southern Mexico. ...CURRENT CONDITIONS AND WEATHER, FOR THE OFFSHORE OIL PLATFORM SITES, THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N NORTHWARD AND FROM 88W WESTWARD... LIFR: none. IFR: KMZG, KBBF, KXIH, KEMK, KHQI, KEHC, KVQT, KEIR, KSPR, KVKY, KMIS, and KDLP. MVFR: KBQX, KHHV, KVAF, KGUL, KGHB, KIKT, and KVOA. CURRENT CONDITIONS AND WEATHER, FOR THE COASTAL PLAINS OF THE U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... from the DEEP SOUTH of TEXAS to Cross City in FLORIDA: LIFR/IFR/MVFR. rain, sometimes heavy and sometimes with thunder, with the current cold front. for the rest of FLORIDA: IFR/MVFR conditions are increasing in coverage along the Florida west coast. light rain in parts of the Florida Keys. THE CARIBBEAN SEA... Large scale upper level anticyclonic wind flow moves through the SW corner of the area, toward Hispaniola, and then curving toward the east and southeast. Middle level-to-700 mb NE wind flow covers the area that is from 16N northward from 80W westward. A surface trough extends from central Panama to NE Nicaragua and E Honduras. The monsoon trough is along 09N/10N between 74W in Colombia beyond 84W near Costa Rica, and into the eastern Pacific Ocean. Precipitation: scattered to numerous strong from 10N to 12N between 77W and 79W. Widely scattered moderate to isolated strong elsewhere from 18N southward between 80W and 86W in Central America. Isolated moderate in the Gulf of Honduras, from 15N to 17N W of 85W. A surface trough is in the E part of the Caribbean Sea, along 18N65W 15N66W 10N68W. Precipitation: isolated moderate rainshowers are from 10N to 16N between 60W and 72W. 24-hour rainfall totals in inches, for the period that ended at 06/0000 UTC, according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.16 in Curacao, and 0.07 in Guadeloupe. ...HISPANIOLA... Upper level NW wind flow is approaching the area from the northwest, from the waters that are between the Bahamas and Cuba. Upper level SW wind flow is approaching the area from the SW corner of the Caribbean Sea. SURFACE OBSERVATIONS...VFR for Port-au-Prince in Haiti. in the DOMINICAN REPUBLIC: Santiago: light rain. MVFR. ceiling 1600 feet. Punta Cana: MVFR. ceiling 1800 feet. VFR elsewhere. The GFS MODEL forecast for 250 mb shows that a ridge will start along the line from Colombia to the Yucatan Peninsula, to a line from Colombia through the Windward Passage. The GFS MODEL forecast for 500 mb shows that anticyclonic circulation center will be just to the east of the Bahamas along 23N, at the start of the 48-hour forecast period. The anticyclonic circulation center eventually will move eastward, more into the Atlantic Ocean, by about 550 nm at the end of the 48-hour forecast period. NW wind flow will be moving across Hispaniola at the start of day one, and the wind flow eventually will become cyclonic with an east-to-west oriented trough by the end of day one. Day two will start with the trough being pushed southward by the Atlantic Ocean ridge and the large-scale anticyclonic circulation center. Expect SE-to-S wind flow during day two. The GFS MODEL forecast for 700 mb shows that day one will start with a NW-to-SE oriented ridge, which will give way to NE wind flow, and then followed by a NW-to- SE oriented inverted trough across the area at the end of day one. Day two will consist of first E- to-SE wind flow across the area, giving way to large-scale SE wind flow as part of the large-scale Atlantic Ocean anticyclonic wind flow. THE ATLANTIC OCEAN... A deep layer trough is moving through the central sections of the Atlantic Ocean. The trough supports a cold front that passes through 32N40W to 25N47W to 25N57W. A surface trough remains from an already-dissipated stationary front from the last 24 hours or so, along 30N40W 23N47W 20N58W. Precipitation: widely scattered moderate to isolated strong from 30N northward between 30W and 40W, and within 45 nm on either side of 30N38W 27N39W 24N42W. rainshowers are possible elsewhere N of 23N between 40W and 60W, and from 18N to 23N between 40W and 78W. For additional information please visit http://www.hurricanes.gov/marine $$ MT