000 AXNT20 KNHC 201731 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 131 PM EDT Thu Apr 20 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... Subtropical Depression ONE has become Tropical Depression One, at 20/1500 UTC. The center of T.D. ONE, at 20/1500 UTC, is near 36.1N 40.0W, in the Atlantic Ocean. T.D. ONE is moving northwest, or 320 degrees, 12 knots. The estimated minimum central pressure is 996 mb. The maximum sustained wind speeds are 30 knots with gusts to 40 knots. Please read the PUBLIC ADVISORIES about Tropical Depression ONE, that are issued under the WMO header WTNT31 KNHC and under the AWIPS header MIATCPAT1. FORECAST/ ADVISORIES about Tropical Depression ONE are issued under the WMO header WTNT21 KNHC, and under the AWIPS header MIATCMAT1. Convective precipitation: widely scattered moderate to isolated strong is within 180 nm to 240 nm to the NE of the line that runs from 32N30W to 35N34W 36N42W 37N48W 39N54W. Isolated to widely scattered moderate from 34N to 38N between 47W and 56W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough passes through the coastal sections of Sierra Leone near 07N12W to 02N17W. The ITCZ is along 02N19W 03N32W 02N36W. Convective precipitation: widely scattered moderate to isolated strong from 06N southward between 20W and 35W. Scattered to numerous strong from 01N southward, to the coast of Brazil, between 46W and 50W. ...DISCUSSION... ...THE GULF OF MEXICO... An upper level cyclonic circulation center is in the SW corner of the Gulf of Mexico near 22N93W. Cyclonic wind flow covers the Gulf of Mexico from 27N southward from 89W westward. Convective precipitation: widely scattered moderate to isolated strong from 25N southward between 83W and 90W Upper level anticyclonic wind flow covers the area that is from 29N southward from 89W eastward. A surface ridge passes through SW Georgia, across the Florida Panhandle, into SE Louisiana, into south Central Texas. ...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: KHQI, KEIR, 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 Hebbronville, at the Corpus Christi NAS, in Bay City, and in Tomball. LOUISIANA: MVFR in Baton Rouge, at the NW corner of Lake Pontchartrain, at the New Orleans NAS, and in Galliano. MISSISSIPPI: MVFR in the Hattiesburg metropolitan area. ALABAMA and FLORIDA: VFR. ...THE CARIBBEAN SEA... Broad middle level-to-upper level anticyclonic wind flow spans the Caribbean Sea, to the east of the line that runs from the southern coast of Cuba that is along 80W, to the central coast of Honduras. The anticyclonic wind flow is related to a Colombia-to-Eastern Pacific Ocean ridge that extends beyond 08N/09N along 90W. Upper level SW wind flow covers the NW corner of the Caribbean Sea, related to the SW Gulf of Mexico upper level cyclonic circulation center. Convective precipitation: scattered moderate to isolated strong from 17N to 19N between 84W and 86W. Broken to overcast multilayered clouds and other possible rainshowers are from 16N northward from 80W westward. Broad surface cyclonic wind flow, in the isobaric pattern, extends from the Windward Passage into the SW corner of the Caribbean Sea. Other areas of convective precipitation: widely scattered moderate to isolated strong from 15N to 20N between 74W and 78W. Scattered moderate to isolated strong from 10N to 12N between 73W and 78W. Rainshowers are possible elsewhere, in scattered to broken low level clouds, across much of the area. 24-hour rainfall totals that are listed for the period that ended at 20/1200 UTC...according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...0.01 in San Juan in Puerto Rico, and in Nassau in the Bahamas. ...HISPANIOLA... Middle level-to-upper level westerly is moving across the island. Hispaniola is on the eastern side of a ridge that extends from Colombia to the Eastern Pacific Ocean near 08N/09N along 90W. Convective precipitation: isolated moderate in the coastal waters, and at some coastal observing sites. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the DOMINICAN REPUBLIC: Barahona: VFR. few cumulonimbus clouds. Santo Domingo: MVFR. ceiling 1800 feet. La Romana: VFR. Punta Cana: light rain. MVFR. ceiling 1800 feet. Santiago: VFR. earlier nearby rainshowers have ended for the moment. Puerto Plata: MVFR. ceiling 1800 feet. The GFS MODEL forecast for 250 mb shows that SW wind flow will cover the area from the start of the 48-hour forecast period, until about 6 hours to 12 hours from the end of the period. A ridge will extend from Colombia into the Eastern Pacific Ocean along 08N90W. The wind flow will shift to the W and NW during the last 6 hours to 12 hours. The GFS MODEL forecast for 500 mb shows that NW wind flow will move across Hispaniola during the next 48-hour forecast period. A ridge will be to the west of Hispaniola. The GFS MODEL forecast for 700 mb shows that broad anticyclonic wind flow, with a ridge, will span the area. ...THE REST OF THE ATLANTIC OCEAN... Upper level cyclonic wind flow covers the area from 20N northward between 20W and 70W. This cyclonic wind flow is moving around the upper level cyclonic circulation center that is close to T.D. ONE. A cold front curves through 32N44W to 28N46W 25N53W 26N65W, and 29N74W. Convective precipitation: rainshowers are possible in areas of scattered-to-broken low level clouds, that are to the north of the line that passes through 32N39W 25N41W 21N50W 23N60W 25N80W. A surface ridge extends from 32N22W, to a 1016 mb high pressure center that is near 24N25W, 14N36W, and 06N53W. For additional information please visit http://www.hurricanes.gov/marine $$ MT