000 AXNT20 KNHC 151714 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 114 PM EDT Tue Aug 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 1200 UTC surface analysis and satellite imagery through 1645 UTC. ...SPECIAL FEATURES... Hurricane Gert is centered near 32.8N 72.0W at 15/1500 UTC or about 365 nm W of Bermuda moving N-NE at 9 kt. Estimated minimum central pressure is 986 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. Numerous moderate to strong convection is within 90 nm in the southeast semicircle of the center. Elsewhere, scattered moderate convection is from 29N to 31N between 70W and 73W. See latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. ...TROPICAL WAVES... A tropical wave is W of the Cape Verde islands reaching from 20N29W to 1010 mb low pressure near 13N32W to 10N32W, moving west at 10 kt. Scattered convection is noted over much of the region from 11N to 14N between 30W and 33W. The wave is in a region of low vertical wind shear, however intrusion of Saharan dry air and dust to the wave environment limit deep convection. Slow development of this system is anticipated during the next day or two, but conditions are forecast to become a little more conducive for tropical cyclone formation by later in the week while the system moves westward over the tropical Atlantic. A tropical wave is in the central Atlc with axis extending from 20N52W to 11N54W, moving W at 10 to 15 kt. The wave is entering a region of moderate to strong vertical wind shear and is being severely affected by extensive Saharan dry air and dust, which is hindering convection at the time. A tropical wave is in the central Caribbean with axis extending from northeast Colombia to central Hispaniola. The wave is in a region of strong vertical wind shear and dry air subsidence, which is hindering deep convection at the time. Divergent flow aloft between an upper trough over the area and an upper ridge well to the northwest is support scattered moderate convection from 150 nm south of the Dominican Republic through the Mona Passage. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of W Africa near 15N17W to 1010 mb low pressure near 13N32W to a 1009 mb low pressure area centered near 14N43W, where the intertropical convergence zone starts and continues to 13N53W then on to near Trinidad. Scattered moderate to isolated strong convection extends from 06N to 11N E of 20W. Scattered moderate convection is within 120 nm of the 1010 mb low pressure near 14N43W. ...DISCUSSION... GULF OF MEXICO... A ridge extends from the Straits of Florida to the coast of south Texas. A broad upper level low is centered just north of the Yucatan peninsula, which supports isolated showers there and in the Yucatan Channel. Diffluent flow in the northwest periphery of the low support similar shower activity off the SE coast of Louisiana and Mississippi. The gradient between the ridge and lower pressure over north central Mexico is supporting moderate to fresh southerly winds across the western Gulf, and light to gentle breezes elsewhere. A surface trough will develop each evening across the Yucatan Peninsula shifting W to the Bay of Campeche during the overnight hours. Locally higher winds can be expected west of the trough axis. CARIBBEAN SEA... A tropical wave is moving through the central Caribbean. Please see section above. The tropical wave will continue to propagate westward across the western Caribbean through late Wednesday. A few showers and thunderstorms are active north of western Panama off Boca del Toro. Showers are also ongoing over the northwest Caribbean from near Swan Island to the Bay Islands, in the divergent flow aloft southeast of the upper low centered north of the Yucatan peninsula. Otherwise, fresh to strong winds in the south-central basin will through Thursday. ...HISPANIOLA... An upper level trough reaching across the area from the central Atlantic will drift WSW to the north and across the island over the next couple of days supporting scattered showers over the island and adjacent waters through Thursday. ATLANTIC OCEAN... Scattered showers and tstms are N of 28N between 70W and 74W associated with the rainbands of Hurricane Gert centered north of the area. See Special Features section for more information on Gert. Otherwise, the remainder basin generally N of 20N is under the influence of the Azores high, which supports fair weather. For information about tropical waves, see section above. Farther east, numerous moderate to isolated strong convection is noted across sub-Saharan West Africa, related tropical wave activity moving through the region. Some of this convection is observed within 180 nm of the coast from Liberia to Senegal. For additional information please visit http://www.hurricanes.gov/marine $$ Christensen