000 AXNT20 KNHC 140000 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 705 PM EST TUE DEC 13 2016 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. ...THE ITCZ/THE MONSOON TROUGH... The Monsoon Trough reaches the coastal sections of Liberia near 06N10W to 06N13W. The ITCZ continues from 06N13W to 06N21W and 04N32W and 05N35W. Convective precipitation: scattered moderate to strong from 06N to 08N between 17W and 20W. widely scattered moderate to isolated strong elsewhere from 10N southward from 40W eastward, in disorganized precipitation. rainshowers also area from 09N southward between 50W and 60W A surface trough is along 08N42W 06N43W 03N44W. Convective precipitation: isolated moderate from 10N southward between 40W and 50W. ...DISCUSSION... ...THE GULF OF MEXICO... Upper level westerly wind flow moves from Texas, and from 23N along the coast of Mexico northward, into the western half of the Gulf of Mexico, from 23N northward. Upper level SW wind flow moves through Mexico, into the Gulf of Mexico. It is within 120 nm on either side of the line that passes through 21N97W at the coast, to 24N90W, beyond 28N80W. Comparatively drier air in subsidence is apparent in water vapor imagery from 29N southward. A surface ridge passes through a NE Gulf of Mexico 1019 mb high pressure center, into the central Gulf of Mexico, to 23N94W, to an inland Mexico 1020 mb high pressure center that is near 22N101W. ...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: KMIS. MVFR: KBBF, KBQX, KXIH, KVAF, KGUL, 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: MVFR in Edinburg. a mixture of LIFR/IFR/MVFR in the middle Texas coastal plains. MVFR from Victoria to Sugar Land. MVFR from Ellington Field to Conroe. MVFR in Beaumont/Port Arthur and Jasper. LOUISIANA: MVFR from parts of the Lake Charles metropolitan area to Patterson and Galliano. thunder and rain in Baton Rouge, and on the north side of Lake Pontchartrain. light rain at the NAS New Orleans. MISSISSIPPI: a mixture of LIFR/IFR/MVFR along the Gulf of Mexico coast. rain and thunder and LIFR/MVFR from Natchez to Hattiesburg. ALABAMA: MVFR from the immediate coastal plains to Evergreen. thunder and rain in Fort Rucker. FLORIDA: light rain in Milton and Marianna. MVFR from Pensacola westward. ...THE CARIBBEAN SEA... An upper level ridge extends from the coastal sections of north central Venezuela, northwestward, to the Yucatan Peninsula. Comparatively drier air in subsidence is apparent in water vapor imagery from 75W eastward. The monsoon trough is along 10N from 74W in northern Colombia beyond NW Costa Rica. Convective precipitation: isolated moderate from 13N southward from 76W westward. 24-HOUR rainfall totals in inches for the period ending at 13/1200 UTC...according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are 0.54 in Trinidad, 0.43 in St. Thomas in the U.S.A. Virgin Islands, 0.34 in Freeport in the Bahamas, 0.09 in San Juan in Puerto Rico, 0.07 in Curacao, 0.05 in Guadeloupe, and 0.01 in Merida in Mexico. ...HISPANIOLA... Upper level SW wind flow is moving across Hispaniola. Convective precipitation: Rainshowers are possible across Hispaniola, and in the coastal waters and coastal plains, in areas of broken low level to middle level clouds. Isolated moderate from 20N to 24N between 70W and 74W, in the waters that are around the Bahamas, and to the north of Hispaniola. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR/no ceiling. for the DOMINICAN REPUBLIC: Barahona: VFR/no ceiling. few cumulonimbus clouds. Santo Domingo: nearby rainshowers. MVFR. ceiling at 1700 feet. La Romana: nearby rainshowers have ended for the moment. VFR/no ceiling. few cumulonimbus clouds. Punta Cana: VFR/no ceiling. Santiago and Puerto Plata: VFR/no ceiling. The GFS MODEL forecast for 250 MB shows that an anticyclonic circulation center will be about 180 nm to the south of Puerto Rico. The anticyclonic center is forecast to move SE with time, and then open into a ridge, during the first 18 hours to 24 hours of the 48=hour forecast period. Expect SW wind flow across Hispaniola with the anticyclonic circulation center/ridge. Broad W wind flow spans Hispaniola for the rest of the forecast period. The GFS MODEL forecast for 500 MB shows that an anticyclonic circulation center is along the northern coast of Hispaniola for the first 12 hours. The anticyclonic circulation center moves into the Windward Passage for another 24 hours or so. An E-to-W oriented ridge eventually develops across Hispaniola after the anticyclonic center dissipates. Expect anticyclonic wind flow across Hispaniola for the next 48 hours. The GFS MODEL forecast for 700 mb shows that anticyclonic wind flow will move across the area for the first 18 hours or so, with an E-to-W oriented Atlantic Ocean ridge. An inverted trough will bring NE wind flow, and then cyclonic wind flow, for the rest of the 48-hour forecast period. ...THE ATLANTIC OCEAN... Upper level W-to-NW wind flow covers the Atlantic Ocean from 60W westward. A cold front is along 32N between 67W and 74W. The front becomes stationary from 32N74W, beyond southern South Carolina. Convective precipitation: isolated moderate from 27N to 32N between 57W and 74W. An upper level trough passes through the Madeira Archipelago to the Canary Islands. A cold front passes through 32N22W to 28N30W to 27N36W. The front is dissipating stationary from 27N36W to 26N47W and 25N50W. Convective precipitation: rainshowers are possible to the north of 23N50W 24N40W 25N30W, beyond 32N16W. A surface ridge extends from a 1028 mb high pressure center that is near 34N36W, through 32N43W, 29N59W. 29N71W, into the NE corner of the Gulf of Mexico. For additional information please visit http://www.hurricanes.gov/marine $$ MT