000 AXNT20 KNHC 212321 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Sep 22 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 2300 UTC. ...SPECIAL FEATURES... Peter is downgraded to a Tropical Depression at 21/2100 UTC. At this time, it is centered near 20.5N 65.0W or 140 nm NNE of San Juan Puerto Rico moving WNW at 7 kt. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Numerous moderate to isolated strong convection can be found within 120 nm NE and 90 nm SW semicircles of center. Seas to 12 ft are within 60 nm NE quadrant of Peter. On the forecast track, the center of Peter will remain well north of the Virgin Islands and Puerto Rico tonight and should move well east of the southeastern Bahamas during the next few days. Additional gradual weakening is forecast over the next several days, and Peter could degenerate into a remnant low by Thursday. Rainfall around the southern periphery of Tropical Depression Peter could produce additional rainfall totals of 1 to 4 inches, with storm total accumulations up to 6 inches, across portions of the Northern Leeward Islands, including portions of the Virgin Islands, as well as Puerto Rico and the northern portions of Hispaniola through Thursday morning. This rainfall may lead to areas of urban and small stream flooding. Swells generated by Peter are affecting the northern Leeward Islands and Puerto Rico, and will continue spreading westward to Hispaniola this evening and the Bahamas on Wednesday. These swells could cause life- threatening surf and rip current conditions. 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 Peter NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Storm Rose is centered near 22.5N 37.7W at 21/2100 UTC or 870 nm WNW of the Cabo Verde Islands moving NW at 9 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Seas to 12 ft are within 90 nm NE quadrant of Rose. Due to shear, only a small cluster of deep convection is noted in the eastern quadrant of the storm. The storm should gradually turn toward the north during the next couple of days and move more to the northeast on Friday. Rose could decay into a tropical depression this evening and degenerate into a remnant low by Friday. 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. A small but concentrated area of showers and thunderstorms is redeveloping just N of a 1010 mb low pressure located near 09.5N28.5W or a few hundred miles southwest of the Cabo Verde Islands. This low pressure is along a tropical wave with axis near 28W/29W. Environmental conditions are expected to become more conducive for development, and a tropical depression is likely to form by Thursday or Friday while the system moves westward at 10 to 15 kt across the eastern and central tropical Atlantic Ocean. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 48 hours and a high chance through 5 days. Please, refer to the Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 28W from 16N southward, moving west at 10 to 15 kt. Please, see the Special Features section for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Senegal near 14N17W to a 1010 mb low pressure located near 09.5N28.5W to 08N32W. The ITCZ continues from 08N32W to 07N40W to the coast of Suriname near 06N55W. No significant convection is noted along the monsoon trough or ITCZ. GULF OF MEXICO... Weak high pressure of 1018 mb centered near 26N90W dominates the Gulf waters. This system continues to support gentle to moderate winds and mostly slight seas across the region. Showers with embedded thunderstorms are noted over the most of Florida Peninsula. Plenty of moisture in a southerly wind flow will persist tomorrow over South Florida keeping the likelihood of more showers and thunderstorms. A diffluent pattern aloft is also helping to induce this convective activity. For the forecast, an early season cold front is expected to enter the NW Gulf early Wed and reach from the NE Gulf to central Bay of Campeche by late Thu before stalling, supporting increased winds and seas over the northwest and north-central Gulf Tue night through Thu. Moderate to fresh N-NE winds and seas of 6-8 ft are expected near the Tampico area Wed through Thu. Fresh to strong NW winds and seas up to 8 ft are also expected near the Veracruz region on Thu. Of note, this cold front is forecast to support the first gap wind event, with minimal gale force northerly winds in the Tehuantepec region Wed night into Thu morning. CARIBBEAN SEA... Please read the Special Features section above for details on Tropical Depression Peter which could degenerate into a remnant low by Thursday. An upper-level trough extends from eastern Cuba to near Cabo Gracias a Dios, Nicaragua. On the W side of this trough, strong N-NE winds continue to enhance scattered showers and thunderstorms over most of Cuba. Convection has also flared-up over the Yucatan Peninsula and northern Guatemala. The most recent scatterometer data indicate fresh to locally strong trade winds near the coast of Colombia, and moderate to fresh NE-E winds south of Hispaniola. Gentle to moderate winds are noted elsewhere. Seas are 3 to 5 ft with the strongest winds, and 2-3 ft elsewhere. Seas of 4 to 5 ft are noted across the Caribbean passages of the NE Caribbean in association with swells generated by Peter. For the forecast, gentle to moderate trade winds will persist across the basin during the next several days as Peter continues to move away from the NE Caribbean. ATLANTIC OCEAN... Please read the Special Features section above for details on Tropical Depression Peter, located about 140 nm NNE of San Juan, Puerto Rico, Tropical Storm Rose situated about 870 nm WNW of the Cabo Verde Islands, and a low pressure located near 9.5N28.5W with potential of tropical cyclone formation. The Cumbre Vieja volcano on the island of La Palma in the Canary Islands has been erupting since 19/1410 UTC. Satellite imagery shows volcanic ash approximately 30 nm W of the volcano as well as the hot spot related to the eruption. 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 22/0300 UTC. A cold front enters the forecast area near 31N47W then continues SW and W to near 28N70W to 27N56W to 28N70W where it becomes stationary to near Georgia/South Carolina border. Scattered showers and thunderstorms are affecting the NW Bahamas and the waters E of Florida to about 75W. Isolated showers and thunderstorms are near the frontal boundary between 60W and 70W. A ridge dominates the Atlantic waters E of 35W, including the Azores, Madeiras and Canary Islands. The pressure gradient between this ridge and T.S. Rose is producing an area of fresh to strong E to SE winds within about 300 nm NE of Rose's center. Fresh to strong NE winds are noted off southern Morocco and Mauritania to near 22W. For the forecast west of 65W, gentle to moderate winds and slight to moderate seas will continue through late Wed night, except for moderate to fresh winds between the Bahamas and Cuba and elsewhere between 65W and 70W. Winds will then become light and variable west of 70W through the weekend. A weak cold front will move across the waters east of NE Florida Thu and stall through Sun. A gale-force, non-tropical low pressure system, the remnants of Odette, is located about 700 miles west-northwest of the westernmost Azores. This low could acquire some subtropical characteristics over marginally warm waters during the next few days while it executes a small cyclonic loop over the north-central Atlantic Ocean. However, by the end of the week, this system is expected to encounter more hostile environmental conditions. Additional information on this system, including gale warnings, can be found in High Seas Forecasts issued by the National Weather Service. $$ GR