000 AXNT20 KNHC 092306 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Jul 10 2021 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2245 UTC. ...SPECIAL FEATURES... Post-Tropical Cyclone Elsa is centered near 43.0N 69.5W at 09/2100 UTC or 80 nm ENE of Boston Massachusetts moving NE at 30 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Scattered to numerous moderate to strong convection is noted north of 41N and west of 65W, while a feeding band extends from 29N to 40N between 67W-77W. Across coastal Maine, 2 to 4 inches of rain with isolated totals up to 6 inches are possible through this evening, which could result in considerable flash and urban flooding. Isolated minor to moderate river flooding is also expected. On the forecast track, the center of Elsa will continue to move offshore the northeastern United States coast through this evening. The system is expected to move over Atlantic Canada by late tonight and Saturday. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT5.shtml, Forecast/Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml, and the High Seas Forecast issued by the NWS Ocean Prediction Center at https://ocean.weather.gov/shtml/NFDHSFAT1.php for more details. For marine information within 60 nm of the coast, please see products from your local NWS Weather Forecast Office at www.weather.gov. ...TROPICAL WAVES... A tropical wave extends it axis along 30W and south of 10N, moving west at 10 to 15 kt. Scattered showers are noted from 02N-05N between 25W-31W. A central Atlantic tropical wave with a large amplitude has its axis along 47W and south of 24N, moving west at 15 to 20 kt. No significant convection is noted within this wave at this time. A low amplitude tropical wave extends its axis along 69W and south of 12N, moving west at 10 to 15 kt. Scattered moderate convection is noted along and in the vicinity of the wave affecting Venezuela and adjacent waters south of 13N. A tropical wave extends its axis across Nicaragua and the EPAC along 85W and south of 14N, moving west at 10 to 15 kt. Scattered moderate to isolated strong convection is noted south of 13N and west of 80W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea-Bissau near 11N15W to 08N25W. The ITCZ extends from 06N34W to 05N42W. Scattered moderate convection is noted south of the monsoon trough to 07N between the coast of Sierra Leone and 18W. GULF OF MEXICO... A surface ridge extends from western Atlantic across central Florida to the northern Gulf. Recent scatterometer data depicts pass indicated moderate to fresh SE winds in the Gulf mainly across the western half of the basin, while gentle to moderate SE winds prevail elsewhere. Scattered showers and a few thunderstorms are evident off central Texas coast to off northeast Mexico. Seas are 5 to 7 ft over the western Gulf, 4 to 6 ft seas in the southwestern Gulf and 2 to 4 ft over the eastern Gulf. For the forecast, fresh SE winds will persist over the northwest Gulf between the high pressure and lower pressure over Texas through at least late Sat. Similarly, a trough will form off northwest Yucatan Peninsula, supporting fresh or even strong winds during overnight hours through late Tue. Meanwhile, gentle to moderate winds and slight seas will persist over the eastern Gulf. CARIBBEAN SEA... Please refer to the section above for details on the tropical waves enhancing convection across the basin. Latest scatterometer data depicts fresh to strong easterly winds across the majority of the basin, except the northwestern portion, where gentle to moderate winds prevail. Seas of 13-16 ft are estimated over the south-central Caribbean mainly south of 12N. Seas of 3 to 5 ft are noted over the northwest Caribbean, except over the Gulf of Honduras where fresh winds and seas of 4 to 6 ft prevail. Scattered showers and thunderstorms off Panama and Costa Rica due to trade winds convergence, local drainage flow and perhaps aided by a tropical wave moving through that area. No significant shower or thunderstorms activity is noted elsewhere. For the forecast, the subtropical ridge north of the area combined with the Colombian low will enhance strong winds through the weekend. Strong trades will also prevail in the Gulf of Honduras into Sat, then pulse nightly into the middle of next week. Of note, an atmospheric Kelvin wave along with successive bursts in the easterly trades will influence the formation of a low along the monsoon trough over Panama and Costa Rica, resulting in an enhanced risk of heavy rainfall for these countries and adjacent Caribbean waters through this weekend. ATLANTIC OCEAN... Please refer to the section above for details on the tropical waves moving across the basin. A surface ridge extends across the basin, anchored by a 1033 mb high centered near 36N40W. Recent scatterometer data and buoy observations depict moderate to fresh E winds across the tropical Atlantic south of 20N while gentle to moderate winds prevail elsewhere. Seas range between 3 to 5 ft north of 25N and 5 to 7 ft farther south. For the forecast, the high pressure will lift north of the area by early next week. This will support moderate to fresh E winds south of the ridge axis, with winds pulsing to fresh to strong along the north coast of Hispaniola mainly during the evenings. $$ ERA