000 AXNT20 KNHC 111745 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 145 PM EDT Tue Aug 11 2020 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A broad 1010 mb low pressure centered near 12N39W along a tropical wave. Scattered moderate convection is noted from 06N-15N between 39W-45W. Environmental conditions are expected to be conducive for development to occur, and a tropical depression is likely to form during the next day or so while the disturbance moves westward to west-northwestward at around 10-15 kt across the tropical Atlantic. This system has a high chance of tropical cyclone formation during the next 48 hours. Please see the latest North Atlantic Tropical Weather Outlook for more information. A gale warning has been issued over the Atlantic high seas, as this system is expected to develop gale-force winds in its N semicircle within the next 30 hours as seas build to 8-11 ft. Note that a tropical storm warning will replace the gale warning if/when this system becomes a tropical depression. Please refer to the latest High Seas Forecast product found at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml. ...TROPICAL WAVES... An eastern Atlantic tropical wave axis is along 24N from 04N- 18N, moving W at 10-15 kt. Scattered moderate convection is noted from 09N-14N between 17W-27W. A central Atlantic tropical wave axis is along 57W from 02N-22N, moving W at 10-15 kt. This wave is well depicted in satellite imagery, despite the lack of significant convection. At this time, scattered showers are noted over the northern portion of the wave. A west-central Caribbean tropical wave axis is along 75W south of 20N, moving W at about 10 kt. Scattered showers are noted in the vicinity of the wave. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 21N17W to 12N26W to the Special Features low near 12N39W. The ITCZ extends west of the tropical wave near 10N42W to 10N54W. Aside from the convection related to the tropical waves described above, scattered showers are noted along the monsoon trough mainly east of 30W. GULF OF MEXICO... Surface ridging prevails across the basin, anchored by a 1017 mb high centered near 27N87W. Light to gentle winds persist across the waters N of 25N, while moderate winds are noted offshore of the Yucatan peninsula in the Bay of Campeche. High pressure will maintain a ridge across the northern waters this week, resulting in gentle to moderate winds with slight seas across the area. Fresh to locally strong winds are expected each evening for the next several nights in the eastern Bay of Campeche near the Yucatan peninsula due to local effects. CARIBBEAN SEA... Refer to the section above for details on the tropical wave moving across the basin. Recent GOES-16 satellite imagery show scattered moderate convection over the southwest Caribbean, related to the extension of the EPAC's monsoon trough. Fresh to strong trade winds persist in the south-central waters near the coast of Colombia and in the Gulf of Venezuela. Elsewhere, gentle to moderate winds prevail. Fresh to strong trade winds will prevail across the south-central Caribbean waters through Fri night, with near gale-force winds expected to pulse near the coast of Colombia and in the Gulf of Venezuela for the next couple nights. Fresh winds will pulse for the next several nights through the Windward Passage. Winds and seas will increase over the Tropical N Atlantic waters tonight and Wed as a tropical wave crosses the region. A low pressure system, possibly a tropical cyclone, could increase winds and seas over the waters E of the Leeward Islands Fri through Sat as it moves W-NW across the tropical Atlantic waters. A tropical wave approaching the eastern extent of an active phase of the Madden-Julian Oscillation (MJO) later this week will support enhanced moist low-level convergence and the potential for heavy rainfall across the SW Caribbean. This could result in localized flooding over Central America and northwest South America. ATLANTIC OCEAN... Please see the sections above for more details on a gale warning for the Atlantic high seas and the tropical waves moving across the basin. A surface trough lingers offshore of the NW Bahamas, with scattered showers noted west of 69W. Overall, the pressure pattern remains weak across the subtropical Atlantic, with light to gentle winds over the waters N of 25N. Moderate to locally fresh trades prevail across the central tropical Atlantic, south of 1024 mb high pressure near 32N42W. Earlier altimeter data indicated seas were 6-8 ft in this region. Farther east, fresh northerly winds are noted from the Canary Islands southward to 20N off the coast of Africa. The trough well offshore of the NW Bahamas will dissipate later today. Fresh winds will pulse each night near the coast of Hispaniola and over the approach to the Windward Passage. Winds and seas will increase E of 65W tonight and Wed as a tropical wave crosses the region. A low pressure system, possibly a tropical cyclone, could increase winds and seas E of 65W Fri night through Sat night as it moves W-NW across the tropical Atlantic waters. $$ ERA