000 AXNT20 KNHC 242331 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 431 PM PDT Mon Aug 24 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 2300 UTC. ...SPECIAL FEATURES... Tropical Storm Laura is centered near 21.7N 82.2W at 24/2100 UTC or 30 nm E of the isle of Youth moving WNW at 17 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Laura is now approaching the Isle of Youth in Cuba. On the forecast track, the center of Laura will cross western Cuba this evening and move into the southeastern Gulf of Mexico overnight. Laura is then forecast to move over the central and northwestern Gulf of Mexico Tuesday night and Wednesday, and approach the northwestern coast of the Gulf of Mexico Wednesday night. Strengthening is expected when the storm moves over the Gulf of Mexico, and Laura is forecast to become a hurricane by late Tuesday. Additional strengthening is forecast on Wednesday. Heavy rainfall and storm winds in gusts have been reported in central Cuba today. Recently, Casablanca in Havana reported a wind gust of about 57 kt (105 km/h). The satellite presentation of Laura has improved somewhat with deep convection remaining over the center, and an increase in banding over the southeastern portion of the circulation. Laura is expected to produce total rainfall accumulations of 4 to 6 inches with isolated maximum amounts of 10 inches over Western Jamaica, Western Cuba and the Cayman Islands into tonight. Across the Greater Antilles this heavy rainfall could lead to life- threatening flash and urban flooding, and the potential for mudslides. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml, for more details. Tropical Storm Marco is centered near 29.0N 88.9W at 24/2100 UTC or 10 nm ESE of the mouth of The Mississippi River moving NW at 6 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Gusty winds, heavy rainfall, and lingering coastal flooding are expected from On the forecast track, Marco will move inland over southeastern Louisiana tonight, and across southern Louisiana on Tuesday. Marco along portions of the Gulf Coast through this evening. The deep convection and associated heavy rainfall has being sheared well to the northeast of the exposed center of circulation. As a result, weakening is expected, and Marco is forecast to become a tropical depression tonight and degenerate to a remnant low on Tuesday. Marco is expected to produce total rainfall accumulations of 2 to 4 inches with isolated maximum amounts of 7 inches across portions of the north-central Gulf coast and southeastern United States through Wednesday. Rain totals related to Marco near Apalachicola, Florida reached as high as 11.81 inches on Sunday. Swells generated by Marco are likely to affect portions of the northern Gulf Coast for the next day or so. These swells are likely to cause life-threatening surf and rip current conditions. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml, for more details. ..TROPICAL WAVES... An eastern Atlantic tropical wave has its axis along 22W from 02N to 20N, moving westward at 10 to 15 kt. Scattered moderate convection is noted near the southern end of the wave axis from 04N-08N between 20W-29W. A central Atlantic tropical wave has its axis along 42W from 02N to 18N. It is moving westward at 10-15 kt. This wave is moving through a stable and dry surrounding environment. Only isolated showers are noted near the wave axis. A tropical wave is over the Caribbean along 83W, south of 15N, moving westward at 10-15 kt. Scattered moderate convection is noted across parts of Central America likely associated with the wave and the monsoonal flow on the eastern Pacific. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the northernmost coastal sections of Mauritania southwestward to 10N30N to 09N41W. The ITCZ axis extends from 09N43W to 11N60W. No significant convection is noted. GULF OF MEXICO... Please see the Special Feature section above for further details on Tropical Storm Marco and on Tropical Storm Laura forecast to move into the southeastern Gulf of Mexico overnight. Other than Tropical Storm Marco, generally weak high pressure is present over the area. Latest scatterometer data showed mainly moderate northerly winds across the western Gulf, and light and variable winds across the central Gulf S of 26N. Strong to gale force winds are seen across the Straits of Florida due to the pressure gradient between Laura and the Atlantic ridge. A Gale Warning is in effect in this area through tonight. CARIBBEAN SEA... Please see the Special Feature section above for further details on Tropical Storm Laura forecast to cross western Cuba this evening. Outside convection associated with Tropical Storm Laura, an upper-level low is helping to induce some convective activity over Puerto Rico and Hispaniola, including also the regional Atlantic waters. At the surface, a trough is analyzed over the northern Leeward Islands. The trough is forecast to move westward across the Greater Antilles over the next 24 hours increasing shower and thunderstorm activity. ATLANTIC OCEAN... High pressure of 1022 mb located near 32N72W extends a ridge across the western Atlantic and the Bahamas. The pressure gradient between this high pressure system and Tropical Storm Laura brought a noticeable increase in winds across the waters S of 27N and W of 75W, including the Straits of Florida. Scatterometer data provided observations of fresh to strong E-SE winds within this area, reaching gale force across the Straits of Florida. As previously mentioned, an upper-level is producing scattered showers and thunderstorms across the Atlantic waters N of Puerto Rico and Hispaniola. This system will move westward. The pressure gradient between the E Atlantic high and the lower pressures over W Africa supports near gale force winds over the Canary Islands. $$ GR