je.st
news
Subtropical Storm Leslie Forecast Discussion Number 6
2018-09-24 22:37:39| National Hurricane Center (Atlantic)
Issued at 500 PM AST Mon Sep 24 2018 110 WTNT43 KNHC 242037 TCDAT3 Subtropical Storm Leslie Discussion Number 6 NWS National Hurricane Center Miami FL AL132018 500 PM AST Mon Sep 24 2018 Leslie's cloud pattern has become rather ragged and less organized this afternoon. Visible satellite imagery indicates that the surface circulation has become elongated, from north to south, with multiple cloud swirls rotating within the larger gyre. The initial intensity is held at 35 kt for this advisory and could be generous, based on the earlier partial ASCAT-A wind retrievals. The intensity forecast philosophy remains the same. Leslie is expected to interact with the incoming baroclinic zone approaching from the northwest and begin intensifying as it completes a post-tropical/extratropical transition by mid period. The official forecast is based on the IVCN multi-model intensity consensus through 36 hours, and a blend of the global models after Leslie becomes an extratropical low. Based on a centroid position of the aforementioned multiple surface swirls, Leslie continues to move in an eastward fashion, or 090/6 kt. Leslie should turn toward the east-northeast in 36 hours in response to an approaching mid-latitude trough and associated cold front from the northwest over the central Atlantic. The large-scale models are in good agreement with Leslie completing an extratropical transition at that time. Afterward, the post-tropical cyclone is forecast to become cut off from the mid- to upper-tropospheric westerly steering flow and move cyclonically toward the end of the week between the building Bermuda high to the west and mid-level ridging over the east Atlantic. The NHC forecast now shows Leslie as a strengthening extratropical low through day 5, in agreement with GFS, Canadian, and European models. Subsequently, the wind radii forecast has also been adjusted based on a compromise of the aforementioned large-scale models. FORECAST POSITIONS AND MAX WINDS INIT 24/2100Z 33.0N 47.2W 35 KT 40 MPH 12H 25/0600Z 32.9N 46.2W 35 KT 40 MPH 24H 25/1800Z 32.6N 44.0W 45 KT 50 MPH 36H 26/0600Z 33.4N 41.3W 50 KT 60 MPH...POST-TROP/EXTRATROP 48H 26/1800Z 35.4N 39.9W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 27/1800Z 36.9N 42.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 28/1800Z 36.7N 46.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 29/1800Z 36.2N 48.5W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Roberts
Tags: number
discussion
storm
forecast
Category:Transportation and Logistics