000 AXNT20 KNHC 230535 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Thu Sep 23 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 0000 UTC surface analysis and satellite imagery through 0525 UTC. ...SPECIAL FEATURES... Peter is no longer a tropical depression. At 23/0300 UTC, the remnants of Peter were centered near 22.1N 67.0W or about 225 nm NNW of San Juan Puerto Rico moving NNW at 4 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 25 kt with gusts to 35 kt. Strong wind shear continues to displace the convection to the east of the center. Peak seas are currently near 8 ft and similar seas are expected over the next few days near the track of the remnant low. The remnants are expected to move generally northward over the next couple of days. Gradual weakening is forecast over the next couple of days. Please, read the read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Peter NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Depression Rose was centered near 24.6N 40.9W at 23/0300 UTC or about 1080 nm WNW of the Cabo Verde Islands moving WNW at 9 kt. Estimated minimum central pressure is 1010 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Rose is a swirl of low- level clouds, with the only significant convection occurring about 120 nm southeast of the center. Peak seas are currently near 11 ft and are forecast to decrease below 8 ft by Friday morning. The depression is moving toward the west- northwest. but a northwestward motion is expected tonight, with a turn toward the north forecast by Thursday night. A motion toward the northeast is expected on Friday. Gradual weakening is forecast during the next couple of days, and Rose is expected to degenerate to a remnant low pressure area by early Thursday. Please, read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https:/www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Rose NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Depression Eighteen was centered near 10.2N 35.0W at 23/0300 UTC or about 1700 nm ESE of the N Leeward Islands moving W at 13 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Numerous moderate to isolated strong convection is occurring 200 nm of the center, mainly in the northern semicircle. Peak seas are currently near 12 ft and are forecast to increase to near 16 ft by Friday morning. The depression is moving toward the west and this general motion is expected to continue through early Friday. A slower motion toward the west- northwest is expected later on Friday and continuing into the weekend. The depression could intensify to a tropical storm on Thursday and to a hurricane over the weekend. Please, read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website- https:/www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.D. Eighteen NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A gale-force, non-tropical low pressure system, the remnants of Odette, is located more than 520 nm WNW of the westernmost Azores. Showers and thunderstorms have increased a little near the low, and it could become a subtropical or tropical cyclone while it moves generally southward over marginally warmer waters during the next couple of days. Strong upper-level winds are expected to develop over the system this weekend, which should limit its development. Additional information on this system, including gale warnings, can be found in the latest High Seas Forecast issued by the Ocean Prediction Center at website- https://ocean.weather.gov/mobile/mobile_product.php?=idNFDHSFA1. This system has a medium chance of subtropical or tropical cyclone formation through 48 hours. Please, see the latest Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... At this moment, no tropical waves are in the analysis/surface map between W Africa and the Lesser Antilles, and across the Caribbean Sea. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the Mauritania-Senegal border near 16N16W and then continues SW and W to 08N30W. The ITCZ extends from 05N40W to 05N52W in the coast of French Guiana. Scattered moderate convection is noted well south of the monsoon trough from 04N to 11N and between 27W to the coast of Africa. No significant convection is noted in association with the ITCZ. GULF OF MEXICO... An early season cold front is moving across the Gulf region and extends from the Florida panhandle near Apalachicola to near Tuxpan, Mexico. Fresh to strong northerly winds are observed behind the frontal boundary in a recent scatterometer satellite data and buoy and ships reports, affecting most of the N Gulf. Fresh to strong northerly winds are also occurring in the SW Gulf, especially within 100 nm of the coast of Veracruz. Scattered showers with embedded thunderstorms are noted within 150 nm of the coast of Tamaulipas from 21N to 25N. The southerly flow will persist today across South Florida and the SE Gulf as the frontal boundary slows down, keeping the region unstable with a high chance of showers and thunderstorms developing again later today, especially in the afternoon and evening hours. Seas behind the cold front are 4-7 ft and 2-4 ft ahead of the cold front. For the forecast, the cold front will continue to move southeastward through Thu, stall from roughly Fort Myers, Florida to the coast of Veracruz, Mexico near 18N95W Fri, then dissipate Sat. Fresh to strong winds will follow the front over the northwest and north- central Gulf into tonight. Fresh to strong winds will funnel along the coast of Veracruz Thu, with seas building to 9 ft. Looking ahead, winds and seas will diminish across basin from Sat and into early next week as high pressure builds over the northern Gulf. CARIBBEAN SEA... Please read the Special Features section above for details on the Remnants of Peter located NNW of San Juan Puerto Rico. The thunderstorm activity that developed in the afternoon and evening hours across the islands in the W Caribbean has generally dissipated. Overall, no deep convection is noted across the basin. However, showers and thunderstorms continue to affect parts of Costa Rica, Panama and N Colombia, with most of convection on their Pacific coasts. The weak pressure gradient due to the remnants of Peter just north of basin and typical lower pressures over South America results in gentle to moderate trades across the region as observed in a recent scatterometer satellite pass. Seas in the E Caribbean are 2-4 ft, and 1-2 ft elsewhere. For the forecast, Tropical Depression Eighteen is well to the east over the Tropical Atlantic near 10.2N 35.0W 1008 mb at 0300 UTC moving W at 13 kt. Maximum sustained winds 30 kt gusts 40 kt. Eighteen will continue to intensify as it moves across the Atlantic, becoming a hurricane near 12.5N 46.0W by Sat morning and, reaching 55W east of the Leeward Islands by Mon. Meanwhile, moderate trade winds will persist over much of the Caribbean into early next week, becoming fresh over the south-central Caribbean Sun and Mon. ATLANTIC OCEAN... Please read the Special Features section above for details on the Remnants of Peter, and Tropical Depressions Rose and Eighteen. The Cumbre Vieja volcano on the island of La Palma in the Canary Islands has been erupting since 19/1410 UTC. The volcano is still emitting ashes, mainly around the volcano drifting SSW below 10,000 ft, and NE above 10,000 ft. Marine and aviation interests should monitor this on-going situation by reading Volcanic Ash Advisory issued by Meteo-France at http://vaac.meteo.fr/volcanoes /la-palma/. The next advisory will be issue no later than 23/0900 UTC. A stationary front extends from 31N44W to 27N60W to 31N78W to the coast of South Carolina. An upper level low near Bermuda is interacting with the frontal boundary and the tropical moisture being propelled northward by the remnants of Peter, resulting in scattered showers and a few thunderstorms from 24N to 31N and between 55W and 68W. The E Atlantic remains under the influence of a strong 1033 mb ridge positioned N of the Azores. Satellite-derived wind data indicate fresh NE winds off the coast of Mauritania and the surrounding waters of the Cabo Verde Islands, mainly from 16N to 21N and E of 27W. This is associated with an outbreak of dry Saharan air. Gentle to moderate anticyclonic winds prevail in the rest of the basin. Seas of 3-6 ft are prevalent W of 60W and 4-7 ft E of 60W. For the forecast west of 65W, the remnant low of Peter is near 22.1N 67.0W 1008 mb at 0300 UTC moving NNW at 4 kt. Maximum sustained winds are 25 kt with gusts to 35 kt. This low will continue to weaken as it drifts northeast of the region through Sat cold front will move off the northeast Florida coast tonight, continue to the southeast Thu, stall from 31N77W to near Fort Pierce, Florida by late Thu, then dissipate through early Sun just before a second weak front possibly moves into the region early next week. Farther east, Tropical Depression Eighteen is over the Tropical Atlantic near 10.2N 35.0W 1008 mb at 0300 UTC moving W at 13 kt. Maximum sustained winds 30 kt gusts 40 kt. Eighteen will continue to intensify as it moves across the Atlantic, becoming a hurricane near 12.5N 46.0W by Sat morning and, reaching 55W east of the Leeward Islands by Mon. $$ DELGADO