000 AXNT20 KNHC 152331 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 730 PM EDT Sat Apr 15 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURE... The 12-hour forecast consists of a low pressure center that will be to the N of the area. A cold front will extend from 31N46W to 25N49W to 19N56W. Expect S gale-force winds and sea heights ranging from 10 feet to 11 feet, to the N of 30N within 180 nm to the east of the front. Expect W-to-NW gale-force winds, and sea heights ranging from 10 feet to 15 feet, to the N of 30N between 48W and 54W. Gale-force winds are forecast to be present also at 24 hours and at 48 hours. Please refer to the high seas forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...MONSOON TROUGH/ITCZ... The Monsoon Trough passes through the coastal sections of Liberia near 05N09W to 02N11W. The ITCZ continues from 02N11W, to 01N20W 01N30W, to the Equator along 38W, to the coast of Brazil near the Equator along 48W. Convective precipitation: numerous strong within a 30 nm radius of 01N07W. Isolated moderate from 05N southward. ...DISCUSSION... ...THE GULF OF MEXICO... A middle level to upper level trough passes through the coastal border of Mississippi and Alabama to the Florida Keys. Upper level ridges are on either side of the trough. Convective precipitation: rainshowers are possible within 90 nm on either side of the line that runs from the Louisiana coast near 29N92W to 27N89W 25N85W, and to the coast of Cuba near 23N83W. wwidely scattered moderate to isolated strong from 23N to the coast between 85W and 92W. Broad surface anticyclonic wind flow spans the Gulf of Mexico. A surface ridge extends from the Florida Panhandle to the coast of Mexico near 21N97W. ...LOW LEVEL CLOUD CEILINGS 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: none. MVFR: KVQT, KIKT, and KVOA. LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... TEXAS: IFR in Weslaco, Rockport. LOUISIANA: MVFR in Baton Rouge. Earlier heavy rain that was near Slidell a few hours ago has ended for the moment. VFR elsewhere. MISSISSIPPI: Earlier heavy rain that was near Natchez a few hours ago has ended for the moment. MVFR in Bay St. Louis and Gulfport. ALABAMA: towering cumulus clouds in parts of Mobile. VFR elsewhere. FLORIDA: MVFR in Pensacola. Smoke is being observed in Naples. ...THE CARIBBEAN SEA... Upper level SW wind flow covers the area that is to the east of the line that runs from the central part of Belize beyond SE Cuba. Middle level to upper level westerly wind flow covers the rest of the Caribbean Sea. Rainshowers are possible, in the Caribbean Sea, in scattered to broken low level clouds, from 13N to the Greater Antilles between 60W and 70W, to the SW of the line that runs from the coast of Haiti near 18N74W, to the coast of Nicaragua near 12N84W, and from Honduras northward from 83W westward. 24-hour rainfall totals that are listed for the period that ended at 15/1200 UTC, according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES, MIATPTPAN/SXCA01 KNHC, 0.24 in Guadeloupe, 0.07 in Nassau in the Bahamas, 0.03 in San Juan in Puerto Rico, and a trace in Trinidad. ...HISPANIOLA... Upper level SW wind flow is crossing Hispaniola. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo: VFR. La Romana: VFR. Punta Cana: VFR. Santiago: MVFR. ceiling 2200 feet. Puerto Plata: VFR. The GFS MODEL forecast for 250 mb shows that broad SW wind flow will cover the area for the entire time. A trough ends up to the west of Hispaniola at the end of the 48-hour forecast period. The GFS MODEL forecast for 500 mb shows that day one will start with SW wind flow for the first 6 hours to 12 hours, changing to W wind flow for the rest of day one. Expect W wind flow during day two. The GFS MODEL forecast for 700 mb shows that anticyclonic wind flow will be moving across Hispaniola. A ridge will extend from the east central Caribbean Sea islands to Hispaniola during the next 48 hours. ...THE ATLANTIC OCEAN... An upper level trough passes through 32N56W to 26N55W and 21N61W. A cold front passes through 32N54W to 28N60W and 26N70W. A surface trough extends from a 1008 mb low pressure center that is near 31N52W, to 27N54W and 24N58W. A weakening 1014 mb low pressure center is near 22N63W. Convective precipitation: widely scattered moderate to isolated strong from 25N northward between 45W and 50W. Rainshowers are possible elsewhere from 20N to 25N between 45W and 60W, and from 20N northward between 60W and 80W. A middle level to upper level eastern Atlantic Ocean trough passes through 32N25W to 23N28W and 18N31W. A stationary front passes through 32N23W, to 28N25W, and 25N29W. A surface trough is along 27N22W 20N20W. Convective precipitation: rainshowers are possible from 20N northward between Africa and 40W. A surface ridge is along 09N46W, to 24N40W, beyond a 1019 mb high pressure center that is near 33N39W. Surface anticyclonic wind flow covers the Atlantic Ocean from 20N northward from 70W westward. For additional information please visit http://www.hurricanes.gov/marine $$ MT