000 AXNT20 KNHC 070002 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 802 PM EDT Sun Aug 6 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... A broad area of low pressure, with high potential of becoming tropical cyclone seven overnight, is located over western Caribbean waters near 16.1N 82.7W at 0000 UTC, moving WNW at 10 kt. Maximum sustained winds are 30 kt with gusts to 40 kt. Numerous moderate convection is within 180 nm north semicircle of low center. Scattered moderate convection and isolated tstms are elsewhere from 11N to 20N between 77W and 83W. Potential Tropical Cyclone Seven is forecast to move NW and intensify to a tropical storm tonight near 16.6N 83.6W, continue to 18.0N 85.9W Mon, then move inland near Chetumal Mexico late Mon. Potential Tropical Cyclone Seven will continue through the SW Gulf as a tropical storm Wed and Thu. Refer to the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC for more information. ...TROPICAL WAVES... A tropical wave is in the central Atlc about midway between the Cabo Verde Islands and the Lesser Antilles, and is associated with a 1012 mb low centered near 13N41W. The wave axis extends from 19N36W to the low to 08N43W, and is moving W at 10-15 kt. The wave is mainly in a region of low to moderate vertical wind shear, however it continues to be severely affected by dry air intrusion to its environment as shown by CIRA LPW and satellite enhanced imagery. Isolated showers are within 120 nm of the low center. Some slow development of this system is possible during the next several days while it moves generally west-northwestward across the tropical Atlantic. A tropical wave is just E of the Lesser Antilles with axis extending from 21N58W to 10N59W, moving W at 10-15 kt. This is a very narrow wave, however associated with abundant low level moisture as depicted by CIRA LPW. Middle level diffluent flow support scattered heavy showers and isolated tstms from 16N to 21N between 57W and 60W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 11N16W to 08N24W to 12N35W to 07N45W. The ITCZ extends from 07N45W to 06N55W. Aside from convection associated with the tropical waves, numerous moderate to isolated strong convection is from 05N to 10N between 17W and 23W. ...DISCUSSION... GULF OF MEXICO... Middle to upper level diffluent flow along the northern Gulf support isolated showers generally N of 27N. Water vapor imagery show dry air subsidence across the remainder Gulf, which is supporting fair weather tonight. Stable conditions are also supported by a surface ridge that extends from the Atlc across the Florida Peninsula into the Gulf that support light to moderate S-SE. Potential Tropical Cyclone Seven currently located over west Caribbean waters is forecast to move NW and intensify to a tropical storm tonight near 16.6N 83.6W, continue to 18.0N 85.9W Mon, then move inland near Chetumal Mexico late Mon. Potential Tropical Cyclone Seven will continue through the SW Gulf as a tropical storm Wed and Thu. See Special Features for further details. CARIBBEAN SEA... A broad area of low pressure, with high potential of becoming a tropical storm overnight, is located over western Caribbean waters generating heavy showers and gusty winds. The center of the system will pass north of Honduras tonight and early Monday, then approach the east coast of the Yucatan peninsula Monday afternoon. See the special features for further details. Scattered heavy showers and tstms are along Cuba associated with the tropical disturbance. Similar weather conditions are over the NW basin W of 83W, the western half of Hispaniola, Jamaica and the Windward Passage. Isolated showers are occurring in the Windward Islands associated with a tropical wave that will move into the E Caribbean tonight. Heavier showers are expected for the Leeward Islands overnight being supported by diffluence aloft. See tropical waves section for further details. Rainfall amounts up to 6 inches, with isolated amounts of around 12 inches, are possible across the Yucatan Peninsula of Mexico and Belize through Wednesday associated with the potential tropical cyclone seven. ...HISPANIOLA... Scattered showers are occurring across Haiti and the Windward Passage associated with Potential Tropical Cyclone Seven located in the Caribbean between Jamaica and Honduras. Isolated showers are in the southern half of the Dominican Republic. These showers will continue through Monday. ATLANTIC OCEAN... Two tropical waves are in the central Atlantic, one reaching the Lesser Antilles tonight. See section above. The remainder basin remain under fair weather conditions being supported by a broad surface ridge anchored by a pair of 1022 mb highs...one near 29N70W and another near 28N48W. No major changes expected the next two days. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos