Tropical Storm Victor Forecast Discussion Number 6
ActuCyclone
30 septembre 2021
000 WTNT45 KNHC 302042 TCDAT5 Tropical Storm Victor Discussion Number 6 NWS National Hurricane Center Miami FL AL202021 500 PM AST Thu Sep 30 2021 Victor has been relatively steady in strength during the past several hours. Satellite images continue to show that the storm has a large circulation with numerous curved bands surrounding the center. However, recent microwave images indicate that the cyclone has yet to develop a well-defined inner core, which is likely why the system has not strengthened much despite the favorable environmental conditions. The Dvorak classifications are again unchanged and range from 35 to 45 kt, and on this basis, the initial intensity is held at 40 kt. Victor is still moving west-northwestward, or 290 degrees, at 12 kt. The storm is forecast to continue on that same general track for about another day as it remains on the south side of a deep-layer ridge over the subtropical eastern Atlantic. By late Friday, a mid- to upper-level low is expected to form over the central Atlantic, and that feature should erode the western portion of the ridge. As a result, Victor is expected to turn northwestward by the weekend and then northward by early next week when it is forecast to move in the flow between the ridge and the low. The GFS has shifted westward this cycle and is now not far from the ECMWF track. The new NHC forecast track is nudged westward toward a consensus of the GFS, ECMWF, UKMET, and HMON models. The standard consensus aids could be too far to the east since the latest run of the HWRF, which is a member of those models, is a significant outlier to the east. As mentioned above, although the storm has been in favorable conditions for strengthening during the past day or so, it has not taken full advantage likely due to its broad structure. The favorable environment for Victor should persist for about another 24 hours, so gradual strengthening is possible during that time period. However, by the weekend, the models show Victor moving into a region of moderate to strong southwesterly shear and a progressively drier airmass. These negative factors for the storm along with slightly cooler SSTs should cause Victor to lose strength this weekend and early next week. In fact, some of the models suggest that Victor could dissipate by the end of the forecast period. The new NHC intensity forecast is again a little lower than the previous one, trending toward the HCCA, IVCN, and IVDR consensus aids. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 9.9N 30.0W 40 KT 45 MPH 12H 01/0600Z 10.6N 31.4W 45 KT 50 MPH 24H 01/1800Z 11.6N 33.1W 55 KT 65 MPH 36H 02/0600Z 12.9N 34.6W 50 KT 60 MPH 48H 02/1800Z 14.5N 36.2W 45 KT 50 MPH 60H 03/0600Z 16.4N 38.0W 40 KT 45 MPH 72H 03/1800Z 18.9N 40.0W 35 KT 40 MPH 96H 04/1800Z 23.6N 42.7W 30 KT 35 MPH 120H 05/1800Z 28.0N 42.9W 30 KT 35 MPH $$ Forecaster Cangialosi