499 AXNT20 KNHC 091719 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Fri Jul 9 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...SPECIAL FEATURES... Tropical Storm Elsa is over eastern Long Island near 41.0N, 72.1W. Elsa is moving toward the northeast near 27 kt, and this general motion is expected to continue with an increase in forward speed during the next couple of days. Maximum sustained wind speed is 45 kt with gusts to 55 kt. On the forecast track, the center of Elsa will move near eastern Long Island and the coast of southern New England through this afternoon, and then offshore the northeastern United States coast by this evening. The system should move over Atlantic Canada by late tonight and Saturday. As Elsa moves near southern and coastal New England today, heavy rainfall could lead to considerable flash and urban flooding. Isolated minor river flooding is also expected. 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 is near 29W south of 10N, moving west at 10 to 15 kt. An area of moderate scattered convection within 120 nm east of the wave, south of 5N. A central Atlantic tropical wave with a large amplitude has its axis near 44W south of 24N, moving quickly west at 15 to 20 kt. No convection is noted at this time. A tropical wave near 68W south of 12N in the eastern Caribbean, extends over western Venezuela and eastern Colombia, moving west at 15 to 20 kt. Isolated moderate convection is noted within 60 nm of the coast of Venezuela. A tropical wave is in the far southwest Caribbean along 83W, south of 13N, moving west at 10 to 15 kt. Scattered moderate to isolated strong convection is noted within 60 nm of the coast of Panama and Costa Rica, due in part to the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Guinea-Bissau near 11N15W southwest to 07N25W. The ITCZ extends from 06N31W to 07N43W. 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 northeast Gulf. A 1400 UTC scatterometer pass indicated fresh to strong SE winds in the Gulf west of 90W. The same scatterometer pass indicated fresh SE winds off the Texas coast, between the surface ridge and 1010 mb low pressure over South Texas. Gentle to moderate winds are noted elsewhere, except light breezes are noted along the coast of Florida. Scattered showers and a few thunderstorms are evident off central Texas coast to off northeast Mexico. Seas are 6 to 8 ft over the western Gulf, 4 to 6 ft seas in the southwestern Gulf and 3 to 5 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 each evening, 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... A scatterometer pass from this morning revealed strong trades in the south-central Caribbean. Winds may be near gale-force off the coast of Colombia. Seas are estimated to be as high as 16 ft in the area of near gale-force winds. Seas in excess of 8 ft are also evident as far east as 65W, due to the long duration and fetch of fresh to strong trade winds across the eastern Caribbean. Moderate E winds and 3 to 5 ft seas are noted over the northwest Caribbean, except for within the Gulf of Honduras where winds are fresh with seas 4 to 6 ft. There are 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 to near gale-force winds north of Colombia through midday with strong winds continuing into 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... West of 65W, a surface ridge extends from near Bermuda to central Florida. Recent scatterometer satellite data and buoy observations show moderate to fresh E winds south of the ridge axis through the southern Bahamas. Light to gentle breezes persist along the ridge axis, through the northern Bahamas. The scatterometer data also shows moderate SSW winds north of 29N between 72W and 79W. Scattered moderate convection is also noted in this area of winds. Seas are 3 to 5 ft north of 25N and 4 to 6 ft farther south. For the forecast, the surface ridge extending from Bermuda to central Florida 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 evening hours, reaching westward into the Windward Passage. Elsewhere farther east, 1033 mb high pressure is centered west of the Azores near 36N38W. West of 35W, this supporting gentle to moderate NE to E winds and 4 to 6 ft seas north of 25N, and moderate to fresh trades south of 25N with 5 to 7 ft seas. East of 35W, fresh to strong NE winds and 7 to 9 ft seas are noted north of 15N, and gentle to moderate flow and 5 to 7 ft are noted south of 15N. $$ DELGADO/MORA