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| #944053 (Received by flhurricane at: 11:00 PM 10.Oct.2018) TCDAT3 Hurricane Leslie Discussion Number 59 NWS National Hurricane Center Miami FL AL132018 1100 PM AST Wed Oct 10 2018 The overall cloud pattern of Leslie has become somewhat better organized over the past several hours with increasing convection in the central dense overcast and tighter banding features. A blend of the subjective Dvorak and microwave estimates suggest an initial wind speed of 70 kt for this advisory. Satellite fixes indicate that Leslie has turned toward the east- northeast and is moving faster at about 10 kt. The track forecast really hinges on whether Leslie gets accelerated in southwesterly flow ahead of an eastern Atlantic trough or gets dropped by that trough and turns southwestward around a new subtropical ridge. Sadly, the forecast agreement from the previous advisory has disintegrated, with all of the GFS-based guidance now indicating a track more toward Europe, while the ECMWF/UKMET send Leslie in the exact opposite direction toward the east-central Atlantic. I clearly drew the small straw in having to make Leslie`s forecast tonight because this situation is resulting in one of the largest guidance spreads I have seen, about 1000 miles on day 3 and over 2000 miles at day 5. Furthermore, the corrected-consensus guidance is closer to the GFS guidance, which is way to the northeast of the previous forecast. The new forecast will somewhat reflect the latest guidance, showing an adjustment to the east, but is still hundreds of miles to the southwest of the latest model consensus. Obviously this is a zero-confidence forecast tonight. Marginally warm waters and moderate shear could support additional strengthening of Leslie during the next day or two, although the guidance is generally lower than yesterday. By Saturday, colder ocean waters, higher shear and a drier mid-level atmosphere should cause Leslie to weaken. No significant changes were made to the previous intensity forecast. By Monday, Leslie, whether it follows the forecast track or not, will likely be struggling to produce convection or have already transitioned into an extratropical low. Thus the 5 day point shows post-tropical status, perhaps optimistically, but this seems like the most likely option for now. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 27.9N 41.1W 70 KT 80 MPH 12H 11/1200Z 28.4N 39.4W 75 KT 85 MPH 24H 12/0000Z 29.9N 35.7W 75 KT 85 MPH 36H 12/1200Z 31.3N 30.5W 75 KT 85 MPH 48H 13/0000Z 32.3N 25.0W 70 KT 80 MPH 72H 14/0000Z 32.0N 20.0W 50 KT 60 MPH 96H 15/0000Z 29.5N 20.5W 35 KT 40 MPH 120H 16/0000Z 27.5N 25.0W 30 KT 35 MPH...POST-TROPICAL $$ Forecaster Blake |
