000 AXNT20 KNHC 220605 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 205 AM EDT MON AUG 22 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Fiona has weakened to a tropical depression. Its center is near 23.8N 56.6W at 22/0300 UTC or about 495 nm northeast of the Leeward Islands, moving west-northwest at 16 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. A cluster of heavy showers and tstms is noted from 22N-25N between 54W-58W. Please see latest NHC Forecast/Advisory under the AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. A tropical wave is in the east Atlantic extending from 07N-18N with axis near 23W, moving west at 15 kt within the last 24 hours. The wave is associated with a 1008 mb low that is centered near 11N22W. Abundant moisture in the wave environment, favorable deep layer wind shear and upper level diffluence favors scattered heavy showers and isolated tstms from 05N-14N between 22W and 29W. Environmental conditions are conducive for development, and a tropical depression is likely to form during the next day or two while the system moves westward to west-northwestward over the eastern tropical Atlantic Ocean. The Tropical Weather Outlook gives this system a high chance of tropical cyclone development through the next 48 hours. ...TROPICAL WAVES... Tropical wave is in the central Atlantic extending from 09N-20N with axis near 46W, moving W at 15-20 kt within the last 24 hours. There is a 1008 mb low near 14N46W associated with the wave. The proximity of Saharan dry air and dust to the wave environment continue to limit convection to scattered showers and isolated tstms from 13N-18N between 44W and 50W. The dry air near this system is expected to inhibit significant development during the next few days while the disturbance moves westward to west- northwestward. Environmental conditions could become more conducive for development late this week when the system is expected to move near Hispaniola and the southeastern and central Bahamas. Tropical wave is in the western Caribbean extending from 10N-21N with axis near 77W, moving west at 15 kt within the last 24 hours. CIRA LPW imagery from the surface to 850 mb show large patches of dry air in the wave environment mainly east of the wave axis. Water vapor imagery continue to show strong dry air subsidence across this region of the Caribbean. This results in a tropical wave devoid of convection at the time. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 19N16W to 11N22W to 10N35W. The ITCZ begins near 08N48W and continues to 07N53W. Aside from the convection related to the tropical waves scattered showers are from 05N-11N between 30W-47W. ...DISCUSSION... GULF OF MEXICO... Except for the SW Gulf of Mexico, weak surface ridging prevails across the basin, being anchored by a 1019 mb high near 27N85W. The ridge continue to provide gentle variable flow across the east Gulf and E-SE gentle to moderate flow elsewhere. In the SW basin, a surface trough extends from 23N93W to 18N94W supporting cloudiness and possible isolated showers across the Bay of Campeche. This trough provides NE fresh to strong wind within 120 nm off the Yucatan Peninsula coast. Dry air subsidence support fair weather elsewhere. Winds over the eastern Bay of Campeche are forecast to diminish after Monday sunrise but will return again Monday night as another heat surface trough move off the Peninsula. Mostly gentle to moderate E-SE winds are expected to prevail elsewhere through Tuesday near sunrise. CARIBBEAN SEA... A tropical wave is moving across the western Caribbean, however no showers are linked to it. For more details about it see the tropical waves section. In terms of winds, the passage of this wave across the central basin tightened the pressure gradient to support fresh to strong trade winds S of 16N between 68W and 81W. Divergent flow over Central America support scattered heavy showers and tstms across eastern Nicaragua and within 60 nm of its coast. Similar convection is across western Honduras and southern Belize and within 20 nm off its coasts. Water vapor imagery continue to show very dry and stable air across the remainder Caribbean, thus supporting fair weather. The area of fresh to strong trades is forecast to prevail through Tuesday sunrise. ...HISPANIOLA... Fair weather prevails across the island at this time. Moisture is forecast to increase across the island within the next 24 hours as a surge of moisture reaches Hispaniola. This moisture combined with the local effects will support scattered showers and isolated thunderstorms. ATLANTIC OCEAN... Fiona has weakened to a tropical depression. Please see the Special Features section above for more details. The other features of interest in the basin are two tropical waves with possibilities of becoming tropical cyclones. For more details refer to both Special Features and Tropical Waves sections. The remainder of the area is dominated by a surface ridge anchored by a 1024 mb high centered near 28N38W. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS