000 AXNT20 KNHC 201042 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Mon Sep 20 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 1030 UTC. ...SPECIAL FEATURES... Tropical Storm Peter is centered northeast of the Leeward Islands near 19.1N 59.5W at 20/0900 UTC or 210 nm ENE of the Northern Leeward Islands moving WNW at 12 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. The center of Peter remains exposed under strong southerly shear. Numerous moderate to isolated strong convection is observed within 135 nm to the northeast of the center. Judging from the estimated wind flow and reports from buoy 41044 north of the center, seas are likely reaching up to 15 ft, mainly in the northeast quadrant of the center. Peter is expected to continue on a WNW track with little change in speed through Tue morning, then gradually turn toward the NW Tue night. Strong wind shear should cause Peter to gradually weaken over the next few days. Peripheral rainbands S of Peter have been producing heavy showers across the Northern Leeward. Guadeloupe has received 1.79 inches of rain in the past 24 hours. This trend will continue and spread to Puerto Rico later today. As a result, the chance for urban and small stream flooding will greatly increase through Tue. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Forecast Advisory at https://www.nhc.noaa.gov/text/MIATCMAT1.shtml for more details. Marine interests in the area can read the latest NHC Offshore Waters Forecasts at https://www.nhc.noaa.gov/marine/offshores.php Tropical Storm Rose is centered near 15.9N 32.6W at 20/0900 UTC or 480 nm W of the Southernmost Cabo Verde Islands moving NW at 13 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Seas are peaking at 8 to 12 ft mainly in the northeast quadrant of the center. Numerous moderate to scattered strong convection is noted up to 150 nm from the center. Rose is anticipated to move NW with little change in speed over the next few days. Slight strengthening is forecast through tonight before gradual weakening by Tue. 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. For sea conditions near this system, please read the Meteo-France High Seas Forecast at http://weather.gmdss.org/II.html ...TROPICAL WAVES... An Atlantic tropical wave is along 20W from 19N southward and moving W near 15 kt. An area of low pressure is analyzed along with tropical wave, with and estimate surface pressure of 1009 mb. Scattered moderate to isolated strong convection is seen from 06N to 11N between between 21W and 24W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends across the Senegal coast near 16N16W to near the Cabo Verde Islands at 14N25W. Another segment of the monsoon trough reaches from 08N32W to 06N40W, where it transitions to the ITCZ and continues to 03N50W. No significant convection is evident along the monsoon trough or ITCZ. The eastern end of the Pacific monsoon trough extends from near Cartagena, Colombia to Limon, Costa Rica. No significant convection is noted along this feature. ...GULF OF MEXICO... A weak ridge extends from 1015 mb high pressure in the southeast Gulf near 26N84W westward to the coast of Tamaulipas, south of a trough extending across the northern Gulf from near Panama City, Florida to Brownsville, Texas. No significant shower or thunderstorm activity is evident at this time. Moderate SW winds are noted across the northwest Gulf, with light to gentle breezes elsewhere. Slight seas are observed throughout the Gulf. For the forecast, the weak high pressure will extend across the eastern and central Gulf of Mexico through Tue. This pattern will support continued gentle to moderate winds and mostly slight seas across the Gulf. An early season cold front is expected to enter the northwest Gulf early Wed and reach from the NE Gulf to central Bay of Campeche by late Thu, supporting increased winds and building seas over the northwest and north-central Gulf, late Wed through Thu. Looking ahead, strong NW to N winds and building seas are possible off Tampico Thu and Veracruz late Thu into Fri behind the front. ...CARIBBEAN SEA... An upper trough north of Puerto Rico is supporting scattered showers and a few thunderstorms from the northern Leeward Island to the Virgin Islands. Please read the Special Features section above for details on Tropical Storm Peter which is forecast to track well north of these locations. Elsewhere, divergent flow aloft is supporting a few showers and thunderstorms from Jamaica, to Grand Cayman, to off the Isle of Pines. No other significant shower or thunderstorm activity is noted at this time. Winds are abnormally light across the Caribbean, with only gentle to moderate winds observed with 2 to 4 ft seas, except for light breezes and 1 to 3 ft seas over the northwest Caribbean. For the forecast, Tropical Storm Peter will move to 19.7N 61.4W this afternoon, 20.4N 63.6W Tue morning, and to 21.4N 65.5W Tue afternoon. Peter will weaken to a tropical depression as it continues to move northward toward Bermuda through the rest of the week. As this occurs, trade winds over the south- central Caribbean will diminish through Thu night. Look for associated squalls and thunderstorms to affect the Leeward Islands and adjacent waters through tonight. ...ATLANTIC OCEAN... Please read the Special Features section above for details on Tropical Storm Peter east of the Leeward Islands and Tropical Storm Rose WSW of the Cabo Verde Islands. The Cumbre Vieja volcano on the island of La Palma in the Canary Islands has been erupting since 19/1410 UTC. The ash plume is expected to remain below 1000 ft in the vicinity of the volcano while drifting SE, causing a reduction in visibility. 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/ A few showers and thunderstorms are active along a frontal boundary reaching from 31N58W to 29N70W, where it becomes stationary and continues to 31N73W. An upper low centered near 23N65W is supporting scattered showers and thunderstorms from 21N to 26N between 60W and 62W. The Atlantic ridge stretching west- southwestward from a 1034 mb Azores high to roughly 27N60W continues to provide light to gentle winds and 3 to 5 ft seas north of 22N and west of 35W. Outside the influence of Tropical Storm Peter and Rose, gentle to moderate trades and 5 to 7 ft seas are noted elsewhere. For the forecast west of 55W, Tropical Storm Peter will move to 19.7N 61.4W this afternoon, 20.4N 63.6W Tue morning, 21.4N 65.5W Tue afternoon, and 22.4N 67.2W Wed morning. Peter will weaken to a tropical depression near 23.2N 68.0W Wed afternoon, then move to 24.2N 68.4W by Thu morning. Peter will change little in intensity as it moves northward toward Bermuda throughout the rest of the week. Elsewhere west of 70W, gentle to moderate winds and slight to moderate seas will persist over open waters through the early part of the week, with swell to 8 ft associated with the tropical storm reaching the waters east of 72W by Wed. $$ Christensen