000 AXNT20 KNHC 231147 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 647 AM EST Sat Dec 23 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 1000 UTC. ...Gale Warning in the Gulf of Mexico... Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. for Saturday morning: A cold front is forecast to be along 30N90W-20N97W. Expect N gale-force winds, from 21N to 27N W of the front. The gale-force wind conditions will continue until the late night hours of Saturday night/early Sunday morning. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through the Prime Meridian along 05N, to 03N15W and 03N21W. The ITCZ continues from 03N21W to 04N30W 04N39W. Precipitation: isolated moderate to locally strong from 08N southward from 53W eastward. Upper level SW wind flow is to the south of the line that runs from 25N15W at the coast of Africa, to 22N23W, 17N30W 13N50Wand 11N58W. ...DISCUSSION... ...THE GULF OF MEXICO... Broad upper level anticyclonic wind flow spans the entire area, from the SW corner, through the central Gulf of Mexico, beyond Florida. Comparatively drier air in subsidence mostly covers the area that is from 94W eastward. A cold front has reached the NW corner of the Gulf of Mexico, through the SW corner of Louisiana to the Deep South of Texas. Please read the SPECIAL FEATURES section for details about gale- force winds with the cold front. VFR conditions in the Texas coastal plains, after the front passing through there. Broad surface anticyclonic wind flow is in the Gulf of Mexico to the east of the advancing cold front. ...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... MVFR/IFR conditions at many of the sites. CURRENT CONDITIONS AND WEATHER, FOR THE COASTAL PLAINS OF THE U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... TEXAS: VFR conditions in the Texas coastal plains, after the passage of the cold front. LOUISIANA: IFR/LIFR and MVFR in the southern third of the state, to the east of the cold front. VFR behind the front. MISSISSIPPI: LIFR and heavy rain, in some areas, from Natchez-to-Hattiesburg southward. ALABAMA: IFR/LIFR, from Evergreen-to-Dothan southward. FLORIDA: MVFR in Crestview and Tallahassee. LIFR from the Panama City metropolitan area to Marianna, and from Perry to Cross City and Brooksville. IFR/LIFR in the Tampa/St. Petersburg metropolitan area. LIFR from Sarasota to Punta Gorda. MVFR in Fort Myers and in Naples. ...THE CARIBBEAN SEA... A middle level to upper level anticyclonic circulation center is about 90 nm to the WNW of the Cayman Islands. Comparatively drier air in subsidence spans the entire Caribbean Sea. Rainshowers are possible, in areas of broken low level clouds that are spread across the entire Caribbean Sea. 24-hour rainfall totals in inches, for the period that ended at 23/0000 UTC, according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.06 in in Guadeloupe. ...HISPANIOLA... Middle level-to-upper level N-to-NE wind flow is moving across Hispaniola. Large-scale anticyclonic wind flow is moving across the Caribbean Sea at the same time. Comparatively drier air in subsidence in water vapor imagery covers Hispaniola. SURFACE OBSERVATIONS...HAITI, in Port-au-Prince: VFR. in the DOMINICAN REPUBLIC: La Romana: MVFR. ceiling 1600 feet. Punta Cana: light rain. MVFR. ceiling 1600 feet. MVFR in Santiago and Puerto Plata. Low level clouds are moving from the Atlantic Ocean, from 20N63W, to the coast of the Dominican Republic from 70W eastward. The GFS MODEL forecast for 250 mb shows that NW wind flow will move across the area, part of large-scale anticyclonic wind flow. A SE-to-NW oriented trough will cover Hispaniola during the middle part of day one. A Caribbean Sea ridge will push anticyclonic wind flow across the area for the rest of the 48-hour forecast period. The GFS MODEL forecast for 500 mb shows that NE wind flow will move across the area during the next 2 days. An anticyclonic circulation center will be in the Straits of Florida and NW Cuba. The GFS MODEL forecast for 700 mb shows that large-scale NE wind flow will move across the area. An inverted trough will move westward across Hispaniola during the second half of day one. Expect NE-to-E wind flow during day two. ...THE ATLANTIC OCEAN... An upper level trough is along 29N50W to 24N54W to 19N59W, and to 15N63W in eastern part of the Caribbean Sea. A surface trough is along 31N51W 25N53W 19N59W. Precipitation: isolated moderate within 30 nm to 60 nm on either side of 32N47W 27N51W 23N53W 21N57W 18N62W. A stationary front passes through 32N59W to 31N60W. The stationary front is dissipating from 31N60W to 30N64W and 29N69W. A surface trough is along 31N54W 26N67W 26N75W. Rainshowers are possible to the N of the line that passes through 32N50W 24N60W 23N79W. An upper level trough extends from a 27N30W cyclonic circulation center to 22N33W and 17N43W. No significant deep convective precipitation is apparent in satellite imagery. A surface ridge passes through 32N71W, to NW Cuba. Surface anticyclonic wind flow covers the Atlantic Ocean from 20N northward between Africa and 50W. For additional information please visit http://www.hurricanes.gov/marine $$ MT