000 AXNT20 KNHC 120005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Oct 11 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 2315 UTC surface analysis and satellite imagery through 1800 UTC. ...SPECIAL FEATURES... Northern Gulf of Mexico and Western Atlantic Ocean Gale Warning: Low pressure of 999 mb is centered over the NW Gulf near 28N93W. A trough extends from the low south-southwestward to 24N94W and to near 19N96W. A warm front extends from the low eastward to 29N87W and to inland central Florida crossing the coast near Tampa. ASCAT data from this afternoon highlighted gale-force northeast 30-40 kt winds along and within 30 nm north of the warm front and north to northeast gale-force winds of 30-35 kt are west-northwest of the low to near 94W. Strong to near gale force northeast winds are elsewhere north of the warm front. The ASCAT data also showed strong to near gale-force south to southwest winds south of the warm front to near 24N, and fresh to strong south to southwest winds from 22N to 24N between the trough and 87W. Seas are 8-11 ft west of the low and trough and 8-9 ft north of the warm front. The ASCAT data showed fresh to strong southwest to west winds west of the trough to 95W and south to near 23N. Buoy 42002 at 26N93.5W is currently reporting seas to 10.5 ft. Satellite imagery shows numerous moderate to strong convection along and south of the warm front to near 23N. This activity is producing frequent lightning and strong wind gusts. The aforementioned low pressure and front are forecast to move northeast to east across the north-central and NE Gulf this evening, then inland across northern Florida tonight. Scattered to numerous strong thunderstorms and strong to gale- force winds will accompany this low pressure system and frontal boundary across the northern Gulf through tonight. Seas are expected to be at 11 or 12 ft this evening. The low pressure is expected to track eastward across northern Florida tonight, and continue eastward and emerge over the western Atlantic, bringing strong to near gale-force winds east of northern and central Florida tonight into Thu, then shift to east of 75W Thu night, and across the northeast waters Fri through early Sat. Gale-force winds are forecast to affect the northern offshore waters north of 30N through Thu night and north of 27N Fri through Fri evening. Heavy showers and rough seas are expected with this frontal system. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at the website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for details. Tropical Storm Sean is centered near 11.6N 35.3W at 11/2100 UTC or 710 nm WSW of the Cabo Verde Islands, moving WNW at 11 kt. Estimated minimum central pressure is 1006 mb. The maximum sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are presently to 14 ft. Latest satellite imagery shows that Sean is not well organized. Its center is observed to be on the west side of a broken band that consists of numerous moderate to isolated convection roughly from 11N to 12N between 33W-35W. Sean is forecast to assume a west- northwestward to northwestward motion is forecast during the next few days. Little change in strength is forecast during the next 72 hours. 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 Sean NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 20W from 03N to 17N, moving westward 10 kt. A 1010 mb low is located on the wave near 09N. Scattered moderate convection is within 60 nm of 12N22W. This convection has changed little in organization this afternoon, but environmental conditions appear conducive for some slow development over the next few days. This system should move generally westward across the eastern and central tropical Atlantic through early next week. The earlier tropical wave that had moved inland Central America is now over the eastern Pacific. Please see the East Pacific Tropical Weather Discussion (MIATWDEP) for details on this wave. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the coastal plains border areas of Senegal and The Gambia southwestward to the Invest- AL94 1010 mb low pressure center and continues to 10N28W where it pauses east of Tropical Storm Sean. It resumes southwest of Sean near 09N40W to 09N46W, where latest scatterometer data indicates that it transitions to the ITCZ to 10N57W. Scattered moderate convection is within 60 nm south of the trough between 17W-19W. ...GULF OF MEXICO... Please read the Special Features section for details about the ongoing gale event related to low pressure of 999 mb presently over the NW Gulf. A warm front extends from the western Atlantic to across central Florida to near Tampa, and continues westward to a 999 mb low over the NW Gulf near 28N93W. A trough extends from the low south-southwestward to 24N94W and to near 19N96W. Broad low pressure associated with the 999 mb low is over the western and central sections of the Gulf. A weak pressure gradient is over the eastern Gulf. Outside those conditions as described above under the Special Features section, moderate to fresh southerly winds are south of 22N east of the trough to near 87W, and gentle to moderate west to northwest winds are west of the trough from 22N to 23N, and light to gentle northwest winds are south of 22N. Mostly moderate to fresh southeast to south winds are over the eastern Gulf south of 28N, and fresh east winds are north of 28N, except for fresh to strong east winds between 85W-90W. Seas are 4-5 ft over the eastern Gulf south of 28N and 5-7 ft north of 28N. For the forecast, the low pressure and front will move northeast to east reaching the NE Gulf this evening and inland north Florida tonight. High pressure across the Atlantic will build modestly westward into the eastern Gulf Fri through early Sat, before the next cold front moves into the NW Gulf Sat morning and across the entire basin by Sun evening. ...CARIBBEAN SEA... A rather weak pressure pattern remains over the basin. Moderate to fresh east-southeast winds are over most of the basin, except for lighter winds of gentle to moderate speeds over the northeast and northwest parts and light to gentle in the southwestern part of the basin. Generally moderate seas are east of 80W, and slight seas are west of 80W. Subsidence taking place over the vast majority of the basin is inhibiting deep convective activity from developing. Isolated showers and thunderstorms are noted west of 81W and in the southwest part of the sea. For the forecast, moderate to fresh trade winds across the eastern and central Caribbean will diminish to gentle to moderate Fri morning and prevail through Mon night. Fresh to strong southeast to south in the Gulf of Honduras and NW Caribbean will continue through Fri night. ...ATLANTIC OCEAN... Please,read the Special Features section for details about Tropical Storm Sean and on upcoming western Atlantic gale event. Please read the Tropical Waves section for details about the Invest-AL94 low and associated tropical wave. A cold front extends from near 31N49W to 29N62W, where it transitions to stationary front to 29N73W, and continues as a warm front to inland central Florida near Melbourne. Broken to overcast multilayer clouds with pockets of scattered showers and thunderstorms moving eastward are seen north of 24N and west of 45W. Weak high pressure is present over the remainder of the area. A weak surface trough extends from near 31N30W to 27N40W. Numerous moderate to strong convection is east of the trough to near 25N and north of 26N. This activity is quickly shifting eastward. Mostly moderate to some fresh winds are from 26N northward between 45W-60W. Moderate or lighter winds are over the rest of basin. Mostly moderate to some rough seas are north of 26N between 30W-40W. Mostly moderate to slight seas are in the remainder of the Atlantic Ocean. For the forecast W of 55W, aside from the forecast concerning the upcoming western Atlantic gale-force event as described above under Special Features, high pressure will briefly build over the western Atlantic in the wake of the gale event low pressure system, but then a cold front is expected to reach the waters off northeastern Florida Sat and Sat night, followed by moderate to fresh west winds and seas of 3-5 ft. $$ Aguirre