000 AXNT20 KNHC 022315 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Sep 3 2023 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... Tropical Storm Gert is centered near 28.4N 53.8W at 02/2100 UTC or 620 nm ESE of Bermuda, moving NNE at 8 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Gert remains under the influence of strong NE shear, keeping scattered moderate to strong convection within 60 nm to the southwest of the center. Gert's northern movement is governed by its interaction with the nearby Idalia, and it should continue to accelerate north- northeastward tonight and northward tomorrow around the eastern side of Idalia's large circulation. Seas are 12 ft or greater within 90 nm in the southeast quadrant of the storm. Little change in strength is expected before Gert is forecast to open up into a trough of low pressure on Monday. 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 Gert NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Storm Katia is centered near 25.0N 30.5W at 02/2100 UTC or 650 nm NNW of the Cabo Verde Islands, moving NW at 11 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Convection has largely dissipated at least for the short term around Katia, pausing after a strong pulse of convection earlier today. Shear and dry air are expected to cause Katia to weaken through the next 36 to 48 hours as it moves northward, and the system could degenerate into a remnant low on Monday. Please read the latest HIGH SEAS FORECAST issued by Meteo- France at website https://wwmiws.wmo.int/index.php/metareas/affiche/2 and the latest Katia NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gale Warning: Post-Tropical Cyclone Idalia is centered near 32.0N 62.7W at 02/2100 UTC or 110 nm E of Bermuda, moving ENE at 6 kt. Estimated minimum central pressure is 997 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. There may be lingering winds reaching gale force over the waters from 30N to 31N between 60W and 65W, although is is likely diminishing as the system drifts farther north of the area. A large area of mixed swell persists north of 28N between 55W and 70W reaching 12 to 18 ft. A larger area of 8 to 12 ft seas in mostly northerly swell is evident north of 23N west of 50W. These swells are likely to cause life- threatening surf and rip current conditions; please consult products from your local weather office. 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 Idalia NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is along 22W from 18N southward, moving W at 10-15 kt. Scattered moderate convection is from 10N to 12N between 23W and 24W. thunderstorm activity to the south of the Cabo Verde Islands. Environmental conditions appear conducive for some gradual development of this system by the middle part of next week, and a tropical depression is likely to form while it moves westward to west-northwestward at 15 kt over the eastern and central portions of the tropical Atlantic. This tropical wave has a low chance of development through 48 hrs. A Caribbean tropical wave is along 66W, from 18N southward, moving west at 10-15 kt. No significant convection is evident near this tropical wave. A central Caribbean Sea tropical wave is along 76W from 20N southward, moving W at 10-15 kt. A few thunderstorms are active off Colombia near 11N76W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from 10N14W to 05N20W to 06N32W. No significant convection is noted at this time. GULF OF MEXICO... Light to gentle E to SE winds across the northeast Gulf indicate a stalled frontal boundary over that region is rapidly dissipating, leaving a stalled frontal boundary along the northern Gulf coast from Apalachicola, Florida to near Houston, Texas. A few showers and thunderstorms are evident near a surface trough paralleling the Florida coast over the far southeast Gulf. Farther west, a broad surface trough is evident over the southwest Gulf. Fresh NE to E winds may be funneling along the north coast of the Yucatan peninsula behind the trough, but light to gentle winds persist elsewhere with 1 to 3 ft seas. Scattered showers and thunderstorms are moving off the west coast of the Yucatan peninsula following the trough. For the forecast, moderate to locally fresh winds will pulse at night off the NW Yucatan Peninsula through Tue night. A surface trough will move off the Florida Peninsula Mon evening and move towards the north-central basin through Tue evening along with moderate to locally fresh E winds. Otherwise, light to gentle variable winds are forecast from Wed evening through Thu night. CARIBBEAN SEA... Fresh to locally strong trades are noted in the south-central Caribbean, off northwest Venezuela and northeast Colombia, with seas of 5-7 ft. Elsewhere, trades are gentle to moderate with seas of 3-5 ft. Scattered showers and tstorms are noted in the NW Caribbean. For the forecast, fresh to strong trades in the central Caribbean will diminish early this evening due to a weak pressure gradient. Gentle to moderate winds with slight to moderate seas will prevail through the weekend. Fresh winds will return in the central and eastern Caribbean by early next week and continue through Thu night. ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for details about Post-Tropical Cyclone Idalia, Tropical Storm Gert and Tropical Storm Katia. A cold front associated with Post-Tropical Cyclone Idalia extends from 31N61W to the central Bahamas. No significant shower or thunderstorm activity is noted along or near this front. Over the tropical Atlantic, a surface trough extends from 13N36W to 08N48W. Outside of the winds and seas discussed in the Special Features section associated with this system and with Tropical Storms Gert and Katia, and the tropical wave near 22N, mostly gentle to moderate winds and 4 to 6 ft combined seas are present across the Atlantic. For the forecast west of 55W, Idalia will become extratropical and move to 32.5N 61.7W Sun morning, 34.0N 60.0W Sun afternoon, 36.0N 58.5W Mon morning, 38.2N 57.6W Mon afternoon, 40.1N 57.9W Tue morning, and 41.3N 58.9W Tue afternoon. Idalia will change little in intensity as it moves near 43.2N 60.8W Wed afternoon. Gale force winds and very rough seas associated with Idalia will impact the northern waters through Sun morning. Seas will subside by Mon. Meanwhile, Tropical Storm Gert is near 28.4N 53.8W at 5 PM EDT, and is moving north-northeast at 8 kt. Maximum sustained winds are 45 kt with gusts to 55 kt, and the minimum central pressure is 999 mb. Gert will move to 29.8N 53.0W Sun morning, 32.1N 52.0W Sun afternoon, 35.5N 51.5W Mon morning, and dissipate Mon afternoon. $$ Christensen