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| #981750 (Received by flhurricane at: 10:42 PM 09.Sep.2019) TCDAT3 Tropical Storm Gabrielle Discussion Number 27 NWS National Hurricane Center Miami FL AL082019 1100 PM AST Mon Sep 09 2019 Gabrielle`s convection has waned considerably since the previous advisory, and the cloud pattern now has a disheveled appearance that is becoming more reminiscent of an extratropical low pressure system. However, a recent 2246Z ASCAT-A scatterometer pass indicated that the tropical storm has maintained a very robust surface wind field, with peak winds still at 45 kt and a radius of maximum winds of 45-50 nmi. The initial motion estimate is 055/21 kt, based primarily on passive microwave and scatterometer satellite fixes. Gabrielle is now well embedded in the high-latitude westerlies, and an additional increase in forward speed toward the northeast or east-northeast is expected over the next 2 days. By 72 hours, Gabrielle is forecast to dissipate near the northern British Isles. Gabrielle is currently located over sub-25 deg C sea-surface temperatures and within a strong vertical wind shear regime of near 30 kt. With much colder water and stronger southwesterly shear ahead of the cyclone, extratropical transition now appears likely to occur within the next 12 hours. The intensity forecast is similar to the previous advisory, and is a blend of the statistical SHIPS intensity models, and the GFS and ECMWF dynamical model wind fields. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 42.1N 43.1W 45 KT 50 MPH 12H 10/1200Z 44.0N 39.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 24H 11/0000Z 46.6N 34.6W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 11/1200Z 50.1N 27.1W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 12/0000Z 54.0N 16.6W 30 KT 35 MPH...POST-TROP/EXTRATROP 72H 13/0000Z...DISSIPATED $$ Forecaster Stewart |