288 AXNT20 KNHC 021018 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Thu Sep 2 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... Larry is upgraded to hurricane status at 02/0900 UTC. At this time, it is centered near 13.0N 32.3W or 470 nm WSW of the Southernmost Cabo Verde Islands moving W at 17 kt. Estimated minimum central pressure is 987 mb. Maximum sustained wind speed is 65 kt with gusts to 80 kt. On the forecast track, a gradual turn toward the west-northwest and a decrease in forward speed are expected Friday and Friday night. A slightly slower west- northwestward motion is expected on Saturday. Steady to rapid strengthening is forecast during the next couple of days, and Larry is expected to become a a major hurricane by Friday night. Numerous moderate to scattered strong convection is within 60 nm N and 75 nm S semicircles of center. Similar convection is also noted just to the west of Larry covering the waters from 10N-15N between 32W-37W. Hurricane Larry will be accompanied by an expanding wave height field that will send large swells toward the Leeward Islands on Sun. This swell event is forecast to propagate farther west likely reaching the Atlantic waters of Puerto Rico and Hispaniola on Mon. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT2.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT2.shtml for more details. ...TROPICAL WAVES... A tropical wave was added to the surface analysis near the coast of Africa at 0O00 UTC. The wave is now along 18W from 19N southward, moving W at around 15 kt. A cluster of moderate to isolated strong convection is along the wave axis from 12N-15N E of 20W to the coast of W Africa. The axis of a tropical wave is near 52W from 20N southward, moving westward at about 20 kt. A cluster of moderate to isolated strong convection is noted where the wave meets the ITCZ near 07N53W. The wave axis extends into French Guiana. A low amplitude tropical wave is moving westward across the Caribbean Sea with axis along 72W, south of 15N. The wave appears to enhance some convective activity over northern Colombia. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Mauritania near 18N16W to 14N26W, then resumes west of Larry near 12N35W to 08N51W. The ITCZ extends from 08N51W to the coast of Guyana near 07N58W. Aside from convection noted above, another cluster of moderate to isolated strong convection is observed from 09.5N-12.5N between 43W-47W. GULF OF MEXICO... A 1014 mb surface high pressure is analyzed over the Florida Keys. The latest ASCAT data show fresh to locally strong west winds in the NE Gulf to the north of the weak high pressure. Mainly gentle to moderate E to SE winds dominate the remainder of the Gulf, with the exception of light and variable winds over the SE waters thanks to the high pressure center. Seas are 2 to 4 ft across most of the basin, except 4 to 6 ft in the NE Gulf. To the NW of the Yucatan Peninsula, fresh NE to E winds, with 3 to 5 ft seas are occurring due to local effects related to a thermal trough. Scattered showers and thunderstorms are noted over the western Bay of Campeche, and near the Veracruz region. For the forecast, the fresh to strong west winds over the NE Gulf will persist through early this morning ahead of a cold front extending over the SE of United States. Then, light and variable winds will prevail over the NE Gulf during the upcoming weekend. Elsewhere, a ridge will dominate the Gulf region producing mainly gentle to moderate southerly winds through Fri. Pulsing fresh winds are expected northwest of the Yucatan Peninsula at night through Fri. Looking ahead, an area of low pressure that is currently located near the coast of Nicaragua could move over the southwestern Gulf of Mexico during the weekend and early next week, but by then strong upper-level winds would likely limit significant development. CARIBBEAN SEA... Recent satellite derived winds data show gentle to moderate trade winds across the Caribbean Sea, except for fresh to strong winds in the Gulf of Honduras, and fresh E to SE winds near Cabo Gracias a Dios, Nicaragua. Seas are 2 to 4 ft, except 4 to 6 ft in the Gulf of Honduras. A small are of showers with embedded thunderstorms is from 15N-17N between 80W-83W. This convective activity is likely associated with a small area of low pressure located over the coast of NE Nicaragua. For the forecast, a ridge N of the Caribbean Sea combined with lower pressure over northern Colombia will support moderate to fresh trade winds over the south-central Caribbean through Sun. Fresh to locally strong E to SE winds are expected in the Gulf of Honduras at night through the weekend. A small area of low pressure located near the coast of Nicaragua is producing disorganized shower and thunderstorm activity. This low is expected to move inland over Nicaragua this morning, but a portion of the low's circulation could move over the Gulf of Honduras on Friday where development, if any, is expected to be slow to occur. Regardless of development, heavy rains are possible across portions of Central America and the Yucatan Peninsula through the weekend. There is a low chance for tropical cyclone development over the next 48 hours. Please see the latest Atlantic Tropical Weather Outlook at hurricanes.gov for more information on this feature. ATLANTIC OCEAN... Fresh to locally strong SW to W winds are noted just off NE Florida. These winds are occurring ahead of a cold front that extends over the SE of United States. An upper-level low is spinning just NE of the central Bahamas generating scattered showers and isolated thunderstorms from 22N-30N between 62W-73W. A surface trough, the remnants of Kate, extends from 31N53W to 27N57W. Scattered showers and isolated thunderstorms are near the trough axis. Fresh S winds are noted on the east side of the trough, where seas are in the 5-7 ft range based on an altimeter pass. A 1024 mb surface high pressure is near 34N39W and dominates most of the Atlantic forecast waters W of 30W. A belt of moderate to fresh trades are noted from 16N to 23N between the coast of Africa and 45W due to the pressure gradient between the aforementioned high pressure to the N and Hurricane Larry. An occluded low pressure is near the Azores. For the forecast west of 65W, fresh to strong southwest winds off NE Florida will shift northeast of the area by late Thu. These winds are ahead of a cold front forecast to weaken as it moves across the northern waters W of 70W Sat through Sun night. Looking ahead, large swells generated by Hurricane Larry are expected to propagate across the waters NE and E of the Leeward on Sun, likely spreading beyond 65W Mon and Mon night. For the forecast east of 65W, please see the Special Features section for more information on Hurricane Larry forecast to strengthen into a major hurricane Fri night, with seas up to 38 ft. $$ GR