000 AXNT20 KNHC 180005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM Mon Aug 17 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... A far eastern Atlantic tropical wave has its axis along 35W from 03N to 21N, moving westward at 16 kt. It is located about 610 nm west-southwest of the Cabo Verde Islands. This wave has become better defined in the presentation of its associated convection and in its cloud pattern since 24 hours ago. The wave is moving through a very moist surrounding environment. The convection observed with the wave is of the scattered moderate to strong type within 120 nm west of the wave axis from 09N to 12N. Scattered moderate to isolated strong convection in band type formation is within 30 nm of a line from 12N31W to 13N34W and to 12N36W. Scattered moderate convection is within 30 nm of 08N34W and 30 nm of 09N32W. Environmental conditions are conducive for further development, and a tropical depression is likely to form within a couple days while the system moves westward to west- northwestward across the central and western portions of the tropical Atlantic. This system has a medium chance of becoming a tropical cyclone during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave has its axis along 25W from 02N to 21N, moving westward at about 15 kt. This wave is moving through a very moist surrounding environment. Scattered moderate to strong convection is within 180 nm west of the wave axis from 10N to 12N. Scattered moderate convection is within 240 nm west of the wave axis from 07N to 10N and east of the wave axis within 30 nm of 08N24W. This wave is forecast to approach the Special Features tropical wave during the next couple of days. A tropical is approaching the Windward Islands, with its axis along 60W south of 21N. It is moving westward at 15 to 20 kt. Satellite imagery shows clusters of scattered moderate to strong convection from just along the coast of Venezuela near 11N, northward covering just about all of the Windward Islands. The convection extends westward to near 65W and eastward to the waters east of the Windward Islands for about 240 nm. Some observational sites in the Windward Islands recently reported wind gust to 25 kt as well as during the afternoon. This wave is expected to continue to move quickly westward over the eastern and central Caribbean Sea during the next couple of days, which is likely to limit significant development. After that time, however, the system is expected to move more slowly westward across the western Caribbean, where upper-level winds could become more conducive for the development of a tropical depression during the latter part of this week. Regardless of development, locally heavy rainfall and gusty winds are expected over portions of the Windward and southern Leeward Islands through Tue morning. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Mauritania, Africa near 20N16W southwestward to 12N25W and continues westward to 12N35W and to 12N52W. The ITCZ is presently not defined. Aside from the convection related to the tropical waves described above, scattered moderate convection is within 120 nm south of the trough between 43W-48W and within 60 nm north of the trough between 47W-49W. GULF OF MEXICO... An upper-level trough stretches from the southeastern U.S. southwestward to 29N89W and southeastward to near the western tip of Cuba. As of 21Z, a stationary front extends from near Mobile, Alabama to 28N92W and to near Corpus Christi, Texas. Ample moisture across the area is allowing for isolated showers and thunderstorms to exist south of 25N west of 90W and within 30 nm of a line from 23N90W to 25N86W and to near Tampa, Florida. Scattered showers and thunderstorms are inland Mexico from Tuxpan to 25N. Moderate to fresh winds are west of the front per latest buoy observations and a partial ASCAT pass. Light winds remain across the remainder of the basin. As for the forecast, the stationary front will gradually dissipate through mid-week. Elsewhere high pressure centered east of the area will extend over the eastern and southern Gulf, leading to light winds and slight seas. Looking ahead, fresh to strong winds are possible over the south central Gulf ahead of low pressure approaching the region from the northwest Caribbean. CARIBBEAN SEA... See Tropical Waves section above for details on the tropical wave that will be entering the eastern Caribbean tonight. Scattered moderate to isolated strong convection is seen south of 13N to inland Colombia and between 74W-77W and from 11N to 13N between 65W -69W. Similar activity is over the Gulf of Honduras. Isolated showers and thunderstorms are over the northwestern Caribbean Sea north of 17N and west of 80W. A rather light gradient over the area is maintaining moderate to fresh trade winds over the south central Caribbean. Moderate trade winds continue over the eastern Caribbean. Light to gentle trades prevail elsewhere. As for the forecast, generally moderate trades will prevail through much of the basin into late week. A strong and fast moving tropical wave will move across the Windward and southern Leeward Islands tonight, then move across the eastern and central Caribbean Tue and Wed, bringing squally conditions, gusty winds, and potentially heavy rainfall. There is a low chance of tropical development from this wave over the eastern Caribbean, but a medium chance when it slows over the western Caribbean late week. Looking ahead, another tropical wave and low pressure system may approach the Atlantic waters off the Leeward Islands by late Fri and Sat. Generally moderate trades will prevail through much of the basin into late week. A strong, fast moving tropical wave will cross the Windward and southern Leeward Islands today, then move across the eastern and central Caribbean Tue and Wed, bringing squally conditions, gusty winds, and potentially heavy rainfall. There is a low chance of tropical development from this wave over the eastern Caribbean, but a medium chance when it slows over the western Caribbean late week. ATLANTIC OCEAN... See Tropical Waves section above for details on a couple of far eastern tropical waves. A nearly stationary front just offshore the southeastern U.S. while an upper-level trough is progressing eastward across the southeastern U.S. Isolated showers and thunderstorms are north of 29N and west of 68W, while scattered showers and thunderstorms are north of the area between 68W-74W. The remnant trough of former Tropical Storm Josephine extends from near 30N64W to 24N70W and to 22N69W. Scattered moderate isolated strong convection is within 180 nm east of the trough axis from 23N to 27N. Farther east, a broad deep-layer ridge roughly parallels 30N with a surface center of 1019 mb near 29N54W and another one of 1020 mb just north of the area near 33N22W. Scattered showers and thunderstorms are along and to within 80 nm of the coast of Cuba between 75W-78W. Similar convection is over the interior of the northeast part of Haiti and the northwest part of the Dominican Republic. Fresh to strong winds accompany the tropical wave near 607W. Light to gentle winds prevail in the vicinity of the surface ridge. Gentle to moderate winds are present elsewhere north of 20N as were indicated by the latest ASCAT pass there and by buoy observations. As for the forecast, high pressure centered over the central Atlantic will control the weather pattern this week, bringing gentle to moderate mainly southerly winds to the area. Looking ahead, low pressure may form along a tropical wave now over the central tropical Atlantic, bringing strong winds, building seas and squally weather to the Atlantic waters north of the Leeward Islands by Sat. $$ Aguirre