000 AXNT20 KNHC 211000 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 600 AM EDT SUN AUG 21 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... Tropical Storm Fiona is centered near 22.2N 51.7W at 21/0900 UTC or about 647 nm east-northeast of the Leeward Islands, moving northwest at 14 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Convection has significantly reduced over the last couple of hours. Scattered to isolated showers are from 19N-24N between 46W and 53W. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCPAT1/WTNT21 KNHC for more details. Tropical wave is just off the west coast of Africa extending from 06N-19N with axis near 18W. There is a 1009 mb low near 12N18W associated with the wave, which is expected to move at 10-15 kt within the next 24 hours. The wave is within a moderate moist environment and it is in a region of favorable to neutral deep layer wind shear that favors scattered heavy showers and isolated tstms from 06N-15N E of 22W. Environmental conditions appear conducive for gradual development, and a tropical depression is likely to form in a few days while the system moves westward and then northwestward over the eastern tropical Atlantic Ocean. ...TROPICAL WAVES... Tropical wave is in the central Atlantic extending from 07N-18N with axis near 41W, moving W at 15-20 kt within the last 24 hours. There is a 1009 mb low near 13N41W associated with the wave. Intrusion of Saharan dry air and dust to the wave environment continue to limit the convection to scattered showers from 12N-18N between 37W and 45W. Environmental conditions are forecast to be conducive for development, and a tropical depression could form within the next few days while the system moves westward and then west-northwestward across the tropical Atlantic Ocean, through the eastern Caribbean Sea, and then near the Greater Antilles. Tropical wave in the central Caribbean extends from 10N-20N with axis near 72W, moving W at 10 kt within the last 24 hours. Even though the wave is in a region of favorable to neutral deep layer wind shear, strong dry air subsidence from aloft inhibits convection at the time. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 12N16W to 10N30W to 11N36W. The ITCZ begins near 08N46W to the coast of Venezuela near 08N59W. For convection information, see the tropical waves section. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging dominates across the Gulf waters N of 22N, being anchored by a 1016 mb high near 26N84W. The ridge continue to provide gentle variable flow across the east basin and E-SE gentle to moderate flow elsewhere. A surface trough is moving across the Bay of Campeche supporting cloudiness and providing NE moderate to fresh wind E of 94W. Dry air subsidence and unfavorable deep layer wind shear support fair weather elsewhere. Mostly gentle to moderate E-SE winds are expected through late Sunday. Fresh to strong winds are forecast to develop over the Bay of Campeche Monday before sunrise. CARIBBEAN SEA... Water vapor imagery continue to show very dry and stable air across the Caribbean, thus supporting fair weather basin-wide. The exception are isolated heavy showers and tstms within 90 nm off the coasts Costa Rica and Panama associated with the proximity of the east Pacific monsoon trough. A tropical wave remains the main feature across the basin. For more details about the wave see the tropical waves section. The tropical wave in the central Caribbean amplified the area of fresh to strong trades to S of 18N between 68W and 80W. These winds are forecast to prevail through near Tuesday sunrise. ...HISPANIOLA... A tropical wave is moving across the central Caribbean, however very dry air subsiding from aloft is supporting fair weather conditions across the entire Island. These favorable weather conditions are forecast to prevail through Monday near sunrise. ATLANTIC OCEAN... The primary concern in the Atlantic waters S of 30N continue to be Tropical Storm Fiona. Please see the Special Features section above for more details. The remainder of the basin is dominated by a surface ridge anchored by a 1021 mb high near 29N36W. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS