000 AXNT20 KNHC 172356 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 756 PM EDT WED AUG 17 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. ...SPECIAL FEATURES... Tropical Depression Six is centered near 15.1N 37.8W at 17/2100 UTC or about 800 nm W of the Cape Verde Islands moving NW at 14 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Scattered moderate convection is within 90 nm of center. Isolated moderate convection is elsewhere from 11N-14N between 37W-40W. See latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... Tropical wave extends from 13N22W to 22N22W moving W at 15-20 kt. The wave coincides with 700 mb troughing that has emerged off the coast of West Africa between 18W-25W with 850 mb relative vorticity maximized along the wave axis near 13N. The wave remains embedded within the Monsoon Trough and convection is confined to that region widely scattered moderate from 09N-15N between 18W- 26W. Tropical wave extends from 08N47W to 17N46W moving W at 20 kt. The wave continues west as remaining energy propagating away from Tropical Depression Six. Global model data indicates mid-level energy is focused along the wave axis near 14N with plenty of dry Saharan air and dust surrounding the wave. This is resulting in an overall lack of significant deep convection...however...in the vicinity of the Monsoon Trough axis near the southern extent of the wave...isolated moderate convection is from 05N-10N between 44W- 49W. Tropical wave extends from 11N63W to 19N63N moving W at 15-20 kt. The wave coincides with a westward surge of generally low to middle level moisture as depicted by SSMI Total Precipitable Water imagery between 60W-65W. To the east of this moisture much drier air with embedded Saharan dust is noted E to about 50W. Isolated moderate convection is from from 10N-14N between 59W-64W. Tropical wave extends from 10N89W to 19N89W moving W at 20 kt. Most of the energy associated with the wave is noted in the East Pacific region...however scattered to numerous moderate convection is occurring across the Yucatan peninsula... Guatemala...and portions of southern Mexico from 15N-22N between 86W-92W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from the African coast near 13N17W to 15N30W then from 10N39W to 08N51W. The Intertropical Convergence Zone axis extends from 08N51W to 08N59W. Aside from convection associated with the tropical waves...isolated moderate convection is from 07N-09N between 35W-39W. ...DISCUSSION... GULF OF MEXICO... An upper level anticyclonic circulation is centered over NE Mexico near 26N101W and is providing much of the western Gulf with a diffluent environment aloft. This diffluence along with gentle to moderate SE winds and peak daytime heating and instability is generating scattered showers and tstms generally W of a line from the central Louisiana coast near 29N91W to the eastern Mexico coast near 20N96W. The convection spreads inland across interior portions of eastern Texas and much of the lower Mississippi River valley. In addition...farther east...isolated showers and tstms are occurring N of 24N between 85W-92W. This overall synoptic pattern is expected to maintain itself through Saturday as ridging anchors along 28N. CARIBBEAN SEA... Aside from the tropical wave analyzed along 90W bringing scattered showers and tstms to the Yucatan peninsula and Guatemala this evening...isolated showers are possible to the west of the wave across the NW waters and portions of Central America generally W of 83W. The remainder of the basin remains fairly tranquil this evening...however a tropical wave noted along 64W is increasing cloudiness and generating scattered showers and isolated tstms between 60W-64W...including the Leeward Islands and Trinidad and Tobago. Otherwise...mostly clear skies prevail as generally fresh to strong trades prevail between 70W-80W. ...HISPANIOLA... South-southwesterly flow aloft is noted over the island between an upper level low centered over the Florida Straits near 24N81W and an upper level ridge centered over the central Atlc near 24N61W. A few low-level isolated showers are possible through the overnight hours into Thursday...however mostly fair skies are anticipated through Thursday night. Thereafter a tropical wave currently along 64W will approach and increase cloudiness and the possibility of precipitation. ATLANTIC OCEAN... Widely scattered showers and isolated tstms are occurring across the SW North Atlc generally W of 76W this evening as strong easterly flow aloft is noted between an upper level low over the Florida Straits near 24N81W and an upper level anticyclonic circulation centered off the coast of the Carolinas near 35N76W. Farther east...the northern extension of a tropical wave along 64W mainly in the Caribbean Sea is analyzed as a surface trough from 20N63W to 24N63W. Another surface trough is analyzed from 24N66W to 28N66W. This broad area of lower pressure...embedded within the southern periphery of the subtropical ridge anchored near Bermuda as a 1025 mb high...is generating scattered showers and widely scattered tstms from 20N-30N between 59W-68W. This area is more convectively active than the parent tropical wave in the Caribbean Sea due in large part to more favorable upper level diffluence noted on water vapor imagery on the northern periphery of an upper level ridge centered near 24N61W. Otherwise...the remainder of the central and eastern Atlc is under the influence of the previous mentioned subtropical ridge extending eastward from the 1025 mb high along 30N to a 1021 mb high centered west of the Madeira Islands near 31N24W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN