000 AXNT20 KNHC 272354 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 754 PM EDT SAT AUG 27 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 Storm Gaston is centered near 29.2N 54.0W at 27/2100 UTC or about 585 nm ESE of Bermuda moving NW at 8 kt. Estimated minimum central pressure is 993 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Scattered moderate convection is from 26N-32N between 50W-58W. See latest NHC Forecast/Advisory under the AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details. A 1009 mb low is centered across the Florida Straits near 23N79W moving W-NW at 10-15 kt. A surface trough is analyzed from the NW Bahamas near 26N77W through the low center to 21N80W. Scattered moderate convection is occurring across a large area of the SW North Atlc and Caribbean Sea...including inland portions of Hispaniola and Cuba this evening. As the low moves W-NW during the next couple days...increased probability of heavy rainfall... localized flooding...and mud slides are possible across those areas. In addition...heavy rainfall and flooding in possible across the southern Florida peninsula as the low moves into the Gulf of Mexico by Sunday night into Monday. ...TROPICAL WAVES... Tropical wave extends from 10N29W to 17N25W moving W at 10-15 kt. The wave is embedded within the Monsoon Trough axis and is difficult to track. Position is based on interpolation. No significant deep convection is occurring with the wave at this time. Tropical wave extends from 11N85W to 21N83W moving W at 15-20 kt. A portion of energy associated with the wave fractured north a couple days ago and is now analyzed as a 1009 mb low and surface trough extending across the NW Bahamas and central Cuba. The remaining westward moving wave energy however is noted in global model data as 700 mb troughing and 850 mb relative vorticity fields S of 20N between 80W-87W. Isolated moderate convection is from 13N-19N between 82W-87W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends from 16N17W to 07N41W. The Intertropical Convergence Zone axis extends from 07N41W to 03N51W. Scattered moderate convection is from 10N-17N between 14W-18W...and from 05N-08N between 48W-52W. Isolated moderate convection is within 240 nm S of the axis between 18W-38W. ...DISCUSSION... GULF OF MEXICO... An upper level low is noted on water vapor imagery over the NW Gulf near 27N95W that supports a weak surface trough analyzed from 24N90W to the Texas coast near Galveston. Widely scattered showers and tstms are occurring N of 28N between 90W-96W...including inland portions of eastern Texas and much of Louisiana. Over the eastern Gulf...an upper level anticyclonic circulation is centered near 28N84W with favorable lifting mid-level dynamics collocated with the ridging. Together...these two features are generating scattered showers and tstms across much of the eastern Gulf E of 90W and across portions of the southwestern Florida peninsula S of 28N. This overall synoptic pattern is expected to persist through Sunday night as a fractured portion of energy associated with a tropical wave currently in the western Caribbean Sea moves across the Florida Straits and into the SE Gulf waters by Monday. Increased precipitation with locally heavy rainfall and possible localized flooding is anticipated this weekend across the southern Florida peninsula and Florida Keys. CARIBBEAN SEA... The western half basin is under the influence of lower surface pressure values given a tropical wave currently analyzed along 85W and the northern energy of the wave that has fractured north and remains focused on a 1009 mb low centered across the Florida Straits near 23N79W. The tropical wave is providing focus for scattered showers and tstms in the vicinity of 17N85W and across inland portions of Honduras and Nicaragua this evening. Other convection...supported by favorable mid-level dynamics is occurring across the Greater Antilles region stretching from the Mona Passage W-NW to across Cuba. Scattered showers and tstms are occurring N of 15N between 67W-77W...and N of 20N between 77W-85W. This complex tropical wave and associated energy to the north is expected to continue W-NW through Sunday and likely bring an increased probability of precipitation to Central America and the Yucatan peninsula with potential for locally heavy rainfall... localized flooding...and mud slides across the region. Farther east...moderate to fresh trades will re-establish themselves E of 80W on Sunday and increase to fresh to strong across the central Caribbean by Monday night into Tuesday. ...HISPANIOLA... Scattered showers and tstms associated with the broad low pressure area NW of the island are expected to persist through the overnight period into Sunday as the low moves W-NW during the next 24 hours. Gusty winds...heavy rainfall...flash flooding... and mud slides are possible across the island through Sunday. ATLANTIC OCEAN... Aside from Tropical Storm Gaston...a 1009 mb low is centered across the Florida Straits near 23N79W moving W-NW at 10-15 kt. Low-level streamline analysis indicates surface troughing extending from SW of Bermuda as a 1010 mb low near 31N67W SW through the Florida Straits low to the broad area of low pressure across the western Caribbean Sea focused on a tropical wave along 85W. A large area of scattered showers and tstms are occurring from across Hispaniola and Cuba mainly S of 27N W of 70W. With regards to the 1010 mb low centered near Bermuda...most of the ongoing scattered showers and tstms are occurring within the NE periphery of an upper level low centered near 31N73W from 31N- 34N between 66W-70W. The low is expected to drift westward through Monday. Lastly...the eastern Atlc is under the influence of a surface ridge anchored by a 1025 mb high centered near 40N33W. A weak surface trough is analyzed on the southern periphery of the ridging from 22N33W to 28N34W. Isolated showers are possible within 180 nm either side of the trough axis. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN