000 WTNT45 KNHC 300842 TCDAT5 Tropical Storm Victor Discussion Number 4 NWS National Hurricane Center Miami FL AL202021 800 AM CVT Thu Sep 30 2021 Victor is gradually getting better organized. AMSR2 microwave data from 0300 UTC showed that the low-level circulation has become more defined, with most convective banding features located west and southwest of the center. Victor's intensity is now estimated to be 40 kt based on Dvorak estimates of T3.0 and T2.5 from TAFB and SAB, respectively, and objective numbers from UW-CIMSS around 40 kt. Victor's vector is toward the west-northwest (290 degrees) at 11 kt, and this heading should continue for the next 36 hours while the storm is located to the south a deep-layer ridge located over the subtropical eastern and central Atlantic. In about 2 days, a mid- to upper-level low is forecast to develop over the central Atlantic, causing Victor to curve around the western periphery of the ridge, which gets shunted eastward between the Azores and the Canary Islands. The track models are in generally good agreement on this scenario, and most of them are clustered tightly among each other. Two notable exceptions, which are discounted at this time, are the HWRF and ECMWF models. The HWRF, which is stronger than the other models, is way off to the east, while the ECMWF lies off to the south and west, a tendency that we've observed recently with other storms in the deep tropics. The NHC track forecast is not changed much from the previous iteration and lies close to the GFS, HCCA, Florida State Superensemble, and TVCA solutions. If the low-level circulation is in fact becoming better defined as shown by microwave imagery, Victor should be able to continue strengthening for the next couple of days in an environment of low vertical shear and over warm waters of roughly 28 degrees Celsius. The NHC intensity forecast is near the upper end of the guidance during this period and continues to show Victor reaching hurricane strength in about 36 hours. Once the aforementioned mid- to upper-level low forms, strong southerly to southwesterly deep-layer shear is expected to develop over Victor and induce a weakening trend in about 3 days. The intensity forecast has been lowered a bit during the latter part of the forecast period given the trends in the intensity models, but it is not as low as the HCCA and IVCN aids. Interestingly, many of the global models suggest that the shear could be so strong that Victor might weaken to a depression or even degenerate into a remnant low by day 5. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 8.7N 27.3W 40 KT 45 MPH 12H 30/1800Z 9.4N 28.8W 50 KT 60 MPH 24H 01/0600Z 10.2N 30.6W 60 KT 70 MPH 36H 01/1800Z 11.2N 32.3W 65 KT 75 MPH 48H 02/0600Z 12.6N 33.8W 65 KT 75 MPH 60H 02/1800Z 14.4N 35.3W 60 KT 70 MPH 72H 03/0600Z 16.6N 37.0W 55 KT 65 MPH 96H 04/0600Z 22.0N 40.2W 40 KT 45 MPH 120H 05/0600Z 27.3N 41.9W 35 KT 40 MPH $$ Forecaster Berg