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#936412 (Received by flhurricane at: 4:41 AM 17.Aug.2018) TCDAT5 Tropical Storm Ernesto Discussion Number 9 NWS National Hurricane Center Miami FL AL052018 500 AM AST Fri Aug 17 2018 Ernesto is maintaining its strength and status as a tropical storm despite being over very cool 21 deg C waters. Deep convection remains well organized in a curved band that wraps across the eastern half of the circulation. The system is likely benefiting from a moist and unstable airmass, which seems to be the reason why Ernesto has held onto tropical storm status longer than expected. The initial wind speed is again held at 40 kt, using a blend of the latest satellite intensity estimates. The convective organization is not expected to last much longer as Ernesto is tracking over steadily colder waters and will also be moving into an environment of higher shear. These hostile environmental conditions should cause the system to lose its tropical characteristics within the next 24 hours, when the cyclone is forecast to be over SSTs of around 15 deg C. The post-tropical low is expected to gradually decay before it merges with a frontal zone near the United Kingdom in about 48 hours. Ernesto is now well embedded in fast mid-latitude flow, and the latest initial motion estimate is northeastward at 22 kt. An even faster northeastward to east-northeastward motion is expected until the system merges with the frontal zone. The models remain tightly clustered, and the NHC track forecast lies near the middle of the guidance envelope. FORECAST POSITIONS AND MAX WINDS INIT 17/0900Z 45.6N 36.4W 40 KT 45 MPH 12H 17/1800Z 47.8N 31.4W 40 KT 45 MPH 24H 18/0600Z 50.4N 23.2W 40 KT 45 MPH...POST-TROPICAL 36H 18/1800Z 52.5N 14.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 19/0600Z...DISSIPATED $$ Forecaster Cangialosi |