|
Show Selection: |
| #936300 (Received by flhurricane at: 4:39 AM 16.Aug.2018) TCDAT5 Subtropical Storm Ernesto Discussion Number 5 NWS National Hurricane Center Miami FL AL052018 500 AM AST Thu Aug 16 2018 Ernesto has generally changed little during the past several hours. The subtropical storm continues to produce patches of convection in curved bands around the center. The circulation of the system is becoming a little elongated from north to south, and dry air is wrapping into the western portion of the system. The initial wind speed is again held at 35 kt, in agreement with the satellite intensity estimate from TAFB. The subtropical storm has a limited amount of time to strengthen as it will remain over marginally warm waters and in a low wind shear environment for only another 12 hours. After that time, the cyclone is expected to cross over a sharp SST gradient and move into an environment of higher shear. These conditions should cause Ernesto to lose its tropical characteristics in about 24 hours, when the SSTs beneath the cyclone are expected to be near 20 deg C. The post-tropical system will likely maintain its intensity, due in part to its fast forward speed, until it merges with a frontal zone near the United Kingdom this weekend. The storm continues to gradually speed up, and it is now moving north-northeastward at 11 kt. A turn to the northeast with a significant increase in forward speed is expected later today and Friday as a pair of shortwave troughs approach the storm, causing the system to become embedded in the mid-latitude westerlies. The models remain in fairly good agreement, and this track forecast is largely an update of the previous one. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 40.8N 44.1W 35 KT 40 MPH 12H 16/1800Z 42.4N 41.9W 40 KT 45 MPH 24H 17/0600Z 45.0N 37.7W 40 KT 45 MPH...POST-TROPICAL 36H 17/1800Z 47.8N 31.6W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 18/0600Z 50.6N 23.4W 40 KT 45 MPH...POST-TROP/EXTRATROP 72H 19/0600Z...DISSIPATED $$ Forecaster Cangialosi |
