000 AXNT20 KNHC 120511 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 110 AM EDT Sat Aug 12 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...SPECIAL FEATURES... A 1013 mb low is centered near 22N67W. Scattered moderate convection is noted from 20N-25N between 64W-68W. Dry air aloft and unfavorable upper-level winds have limited significant development during the past few days. Environmental conditions, however, are expected to become a little more conducive for development during the next day or two, and this system could become a tropical depression over the weekend. The low is forecast to move generally northwestward through the weekend and is likely to turn northeastward away from the United States early next week. There is a medium chance for tropical cyclone formation during the next 48 hours. ...TROPICAL WAVES... The axis of a tropical wave in the far eastern Atlantic is near 21W from 08N to 20N, moving W at 15-20 kt. Scattered moderate convection is noted within 120 nm west of the wave axis from 07N- 11N. The axis of a tropical wave in the central Atlantic is near 42W from 05N to 19N, moving W at 15-20 kt. Scattered showers are within 180 nm west of the wave axis south of 10N. The axis of a tropical wave in the central Caribbean is near 75W from 05N to 20N. Scattered moderate to isolated strong convection is noted over the western half of Hispaniola. Scattered showers are elsewhere within 90 nm of the wave axis south of 11N. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 14N17W to 10N26W to 11N33W to 07.5N46W. The Intertropical Convergence Zone continues from 07.5N46W to the South American coast near 07N58W. Aside from convection associated with the tropical waves, scattered moderate convection is noted from 06N-12N between 25W- 32W. ...DISCUSSION... GULF OF MEXICO... A 1020 mb high is centered over the NE Gulf of Mexico near 27N88W. A thermal trough has developed over the Yucatan Peninsula earlier this evening and is moving into the southwest Gulf waters. Scattered convection is noted over the southwest Gulf west of the trough axis. Light to gentle anticyclonic flow is noted over the Gulf waters, with the exception of moderate winds noted west of the thermal trough moving off the Yucatan into the southwest Gulf. High pressure will continue to remain centered over the Gulf waters this weekend, with associated anticyclonic flow continuing. A thermal trough will develop each evening over the Yucatan Peninsula, shifting westward into the southwest Gulf during the overnight hours, and dissipating over this area each morning. Locally higher winds can be expected west of the trough axis. CARIBBEAN SEA... A tropical wave is moving through the central Caribbean. See Tropical Waves section for details. The tropical wave will continue to propagate westward, moving west of the area late Sunday night. Fresh to locally strong winds prevail over the south central Caribbean, while gentle to moderate winds prevail elsewhere. These general conditions will prevail through the weekend. ...HISPANIOLA... Active convection continues across the western half of Hispaniola, enhanced by a tropical wave moving across the area. The wave will move further from the area over the weekend. However, expect diurnal convection to flare up each afternoon over the weekend. ATLANTIC OCEAN... Please see the tropical wave section above for more on the tropical waves moving across the Atlantic waters. Also, please see above in the special features section for more on low pressure, and the potential for tropical cyclogenesis, over the southwest north Atlantic waters. Winds are generally in the light to moderate range over the Atlantic waters, with the exception of strong winds prevailing in the vicinity of the low pressure center mentioned above. The subtropical high will strengthen over the central Atlantic this weekend. The pressure gradient will tighten between the area of high pressure and the tropical wave currently over the eastern Atlantic this weekend. This will freshen winds north of the tropical wave by Sunday as the wave propagates westward. For additional information please visit http://www.hurricanes.gov/marine $$ AL