000 AXNT20 KNHC 261138 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 738 AM EDT Wed Aug 26 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 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...SPECIAL FEATURES... The center of Hurricane Laura at 26/0900 UTC is near 26.1N 90.7W. This position is about 270 nm/510 km SSE of Lake Charles, Louisiana and about 290 nm/540 km SE of Galveston, Texas. Laura is moving NW or 310 degrees at 13 knots. The estimated minimum central pressure has lowered to 973 mb. The maximum sustained wind speeds have increased to 95 kt with gusts to 115 kt. Satellite imagery shows that Laura is quickly becoming more symmetrical in its cloud pattern presentation as it continues to improve. The imagery is very impressive in that it shows very deep convection of the numerous strong type over the entire cyclone, except near the center where an eye feature, about 15 nm in diameter, is now evident. This convection is observed within 210 nm of the center in the NE quadrant, within 180 nm of the center in the SE quadrant and within 90 nm of the center in the W semicircle. Laura is growing in size and is forecast to strengthen into a major hurricane this afternoon near 27.4N 92.4W with maximum sustained winds 115 kt gusts 140 kt and approach the Upper Texas and southwest Louisiana coasts this evening before moving inland near those areas tonight or Thu morning. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and the Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml, for more details. ..TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 32W/33W from 02N to 18N, moving westward at 15-20 kt. Scattered moderate convection is within 180 nm east of the wave axis from 07N to 10N and within 120 nm west of the wave axis from 09N to 10N. A central Atlantic tropical wave has its axis along 55W south of 18N. It is moving westward at about 17 kt. No deep convection is noted with wave as it is moving through a stable surrounding environment. Only isolated showers and thunderstorms are seen west of the wave from 07N to 14N. The previous tropical wave that was along 91W/92W is now south of the Gulf of Tehuantepec region. Please see the eastern Pacific Tropical Weather Discussion for details on this wave. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the central part of the coastal sections of Mauritania southwestward to 15N25W to 11N33W and to 07N51W where overnight scatterometer data indicates that it terminates. The ITCZ axis extends from just west of the central Atlantic tropical wave to just inland the coast of Venezuela at 08N61W. Scattered moderate to isolated strong convection is increasing over the far eastern Atlantic south of the trough from 09N to 17N and east of 21. Scattered moderate to isolated strong convection is also within 30 nm of line from 10N29W to 10N24W and to 10N21W. Similar convection is within 90 nm south of the trough between 37W-40W. Scattered moderate convection is within 120 nm north of the trough between 34W-37W. GULF OF MEXICO... Please see the Special Features section above for details on rapid intensifying Hurricane Laura, soon to be a major hurricane. What was the post-tropical/remnant low of Marco has now opened up to a trough per latest ASCAT data. It extends from south of Galveston near 27N95W northward to Galveston and to northeastern Texas. NWS Doppler radar indicates scattered showers and isolated thunderstorms over the NW Gulf north of 25N and west of 95W. Otherwise outside Hurricane Laura, broad low pressure covers the basin except for northeast of Laura where western Atlantic high ridges westward to the far NE Gulf. The gradient between Laura and the high pressure is allowing for fresh southeast winds to exist over the southeastern Gulf west of 83W. These winds will diminish today as Laura moves further away from the eastern Gulf. Hurricane Laura centered near 26.1N 90.7W 973 mb at 5 AM EDT is moving WNW at 13 kt. Maximum sustained winds have increased to 95 kt gusts 115 kt. Laura will strengthen into a major hurricane this afternoon near 27.4N 92.4W with maximum sustained winds 115 kt gusts 140 kt, and continue over the NW Gulf to along the coast near 29.7N 93.5W late tonight with maximum sustained winds 105 kt gusts 130 kt. Laura will move inland and weaken to a tropical storm near 32.4N 93.7W Thu afternoon and weaken further to a tropical depression well inland near 34.8N 92.9W late Thu night. Expect long-period swell from Laura to impact most of the basin through Thu. Atlantic high pressure will build westward over the eastern Gulf in the wake of Laura. CARIBBEAN SEA... An elongated upper-level low is identified to be southwest of Jamaica near 17N83W, with a shear axis stretching northeastward to the Windward Passage and continuing from there to the Atlantic near 22N70W. This feature has helped to destabilize the atmosphere over much of the central Caribbean. Scattered showers and thunderstorms are increasing from 11N to 15N between 73W-77W and from 11N to 16N west of 77W to the coast of Honduras. Similar activity is also increasing over the northwestern Caribbean from 16N to 22N between 78W-84W. Isolated showers and thunderstorms are elsewhere over the basin and over sections of southern and eastern Cuba and Hispaniola. Atlantic high pressure will gradually shift southward through the next few days. Expect an increase of trade winds in the central and northeastern sections of the Caribbean Sea. A tropical wave is expected to move across the eastern Caribbean Sea from Thu through Fri accompanied by scattered showers and thunderstorms, some possibly with gusty winds. ATLANTIC OCEAN... An upper-level shear axis extends from an elongated upper-level over the central Caribbean northeastward to near 22N70W. A trough extends from near 27N70W to Haiti. Scattered showers and isolated thunderstorms are south of 24N between 67W-72W and from 22N to 27N between 72W-77W. This activity is translating to the west with time. An elongated upper-level low is located near 27N34W and is slowly moving westward. A trough extends from this low to near 14N39W. Broad surface anticyclonic wind flow covers the rest of the Atlantic north of 20N, with a 1021 mb high centered well to the northeast of the area at 38N20W and a 1020 mb high over northern Georgia. Ocean from 20N northward, from 65W eastward. High pressure just to the north of the area will shift gradually shift southward through the rest of this week and into Saturday. A cold front will reach the southeastern coast of the U.S.A. late on Saturday, and it will reach to just north of the area on Sunday. Fresh southwest winds will precede the front. $$ Aguirre