000 AXNT20 KNHC 251806 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 206 PM EDT THU AUG 25 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... Gaston weakened to a tropical storm at 25/1500 UTC. Its center is near 20.4N 44.4W or about 1008 nm east-northeast of the Leeward Islands moving northwest at 15 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Numerous moderate convection is from 20N to 23N between 42W and 45W. Scattered moderate convection is elsewhere from 18N to 27N between 40W and 51W. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCPAT2/WTNT22 KNHC for more details. ...GALE WARNING FOR SOUTHWEST ATLANTIC... A Gale warning continues in effect for the area northeast and east of a broad area of low pressure analyzed as a 1008 mb low north of Hispaniola near 21N70W. These winds are expected to continue through early Friday morning. Scattered moderate to isolated strong convection is from 16N to 23N between 64W and 75W including Hispaniola and adjacent waters. Environmental conditions have the potential to become more conducive for tropical development and this system could become a tropical depression during the next couple of days when the system is near the central or northwestern Bahamas. Regardless of development, heavy rains are likely over Puerto Rico today, and strong winds and heavy rainfall are likely over portions of Hispaniola, the Turks and Caicos, and the southeastern and central Bahamas during the next couple of days. These rains could lead to flash floods and mudslides. There is a medium chance of tropical development in the next 48 hours. ...TROPICAL WAVES... A tropical wave came off the West Coast of Africa near 0000 UTC today. Saharan dry air and dust cover most of the wave environment, which along with unfavorable deep layer wind shear hinder convection at the time. ...ITCZ/MONSOON TROUGH... The monsoon trough extends across Africa into the east Tropical Atlantic near 18N16W then continues along 08N22W to 06N35W. The ITCZ is not currently evident. Scattered moderate convection is from 05N to 10N E of 17W. ...DISCUSSION... GULF OF MEXICO... A broad middle to upper level ridge is anchored over Tennessee covering the Gulf waters north of 25N. An elongated upper trough extends from the northern Bahamas SW to the Yucatan peninsula. Diffluent flow between these two upper features along with abundant moisture support scattered to isolated heavy showers and tstms N of 24N between 85W and 95W. In the SW basin, a surface trough along 23N92W to 18N94W support isolated showers in the Bay of Campeche. A weak surface ridge extends from the northwest Atlantic across the southeast CONUS to over the north Gulf and is anchored by a 1023 mb high over Georgia. This surface ridge will persist through Sunday. CARIBBEAN SEA... The main concern affecting the basin is the area of low pressure in the Special Features centered just north of Hispaniola. Please see the Special Features section above for the activity associated with this system over the north-central and northeast Caribbean. The elongated upper trough extending across the SE Gulf of Mexico and the Yucatan Peninsula generates diffluent flow just in the vicinity of western Honduras and Belize to support scattered showers and isolated tstms S of 19N W of 86W. Scattered showers are within 90 nm off the coast of southern Panama associated with the east Pacific monsoon trough. East to southeast moderate winds dominate the central and eastern Caribbean waters while gentle NW flow covers the western portion of the basin. The area of low pressure in the Special Features will continue to track northwestward during the next two days generating showers for the Greater Antilles including Cuba. ...HISPANIOLA... Scattered heavy showers and isolated tstms are across the central and souther portions of the Island associated with a broad area of low pressure centered over northern adjacent waters. Shower activity assciated with this low will continue through Sunday potentially causing flash floods and mud slides over portions of the island during the next couple of days. Please see the Special Features section for further details. ATLANTIC OCEAN... The primary concern in the basin is Tropical Storm Gaston in the central Atlantic and an area of Gale-force winds associated with a broad area of low pressure centered N of Hispaniola. Please see the Special Features section above for the activity associated with this system over the southwest Atlantic. The remainder of the east Atlantic is dominated by a surface ridge anchored by a 1025 mb high southwest of the Azores. The Special Features low will track northwestward through the Bahamas into the weekend with gale force winds northeast of the surface low. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS