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Hurricane Leslie Forecast Discussion Number 63
2018-10-12 04:42:45| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Thu Oct 11 2018 000 WTNT43 KNHC 120242 TCDAT3 Hurricane Leslie Discussion Number 63 NWS National Hurricane Center Miami FL AL132018 1100 PM AST Thu Oct 11 2018 Satellite images indicate that Leslie has continued to strengthen. A small eye has occasionally been apparent, although it has recently become obscured by clouds. ASCAT data showed peak winds of 75 kt earlier, and given the low bias of that instrument at those wind speeds, the initial wind speed is set to 80 kt. Leslie should begin to weaken in about 24 hours as the hurricane encounters cool waters and a higher-shear environment. Intensity guidance is tightly clustered around the previous NHC prediction, and little change is made in the new advisory. By 72 hours, a combination of very dry air aloft, waters near 23.5C, and high shear should cause Leslie to lose convection and transition into a post-tropical cyclone. Leslie continues to accelerate east-northeastward with an initial motion estimate of 070/23 kt. The hurricane should move rapidly in that general direction for the next day or so ahead of a mid-latitude trough, then bend eastward and southward as the main steering mechanism switches to the eastern Atlantic subtropical ridge. There is still a large guidance spread, over 700 miles at day 3, but the main change to report is that more of the models are continuing the east-northeastward track longer, possibly due to Leslie becoming a stronger system. The official forecast is shifted to the east, but is still well to the southwest of the model consensus, ironically similar to last night's forecast. Leslie is a fairly large tropical cyclone and the forecast wind radii encompass Madeira Island within 36 hours. Consequently, a tropical storm warning has been issued for that island. It is the first known tropical storm warning for that place, and there are no known tropical storms in the historical record anywhere within 100 miles of that island, with the closest being Vince of 2005. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 30.9N 33.9W 80 KT 90 MPH 12H 12/1200Z 32.1N 29.8W 80 KT 90 MPH 24H 13/0000Z 33.3N 23.5W 75 KT 85 MPH 36H 13/1200Z 34.0N 18.0W 65 KT 75 MPH 48H 14/0000Z 33.5N 15.5W 55 KT 65 MPH 72H 15/0000Z 31.5N 15.0W 35 KT 40 MPH...POST-TROPICAL 96H 16/0000Z 29.0N 18.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 17/0000Z 28.0N 24.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Blake
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