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Tropical Storm Rene Forecast Discussion Number 4
2020-09-08 04:32:00| National Hurricane Center (Atlantic)
Issued at 200 AM CVT Tue Sep 08 2020 000 WTNT43 KNHC 080231 TCDAT3 Tropical Storm Rene Discussion Number 4 NWS National Hurricane Center Miami FL AL182020 200 AM CVT Tue Sep 08 2020 Convection has noticeably waned during the past few hours as Rene's center moved directly over Boa Vista island between 07/2200 UTC and 08/0000 UTC. The highest observed wind speed thus far has been a 10-minute average wind of 25 kt at Sal/GVAC. Satellite intensity estimates range from 35 kt from TAFB to 30 kt from SAB. A 07/2323 UTC ASCAT-B overpass indicated peak winds of 27 kt, but land obscuration likely has resulted in some missed higher wind speeds. For now, the intensity will remain at 35 kt. The initial motion is 280/12 kt. A westward motion is expected today, followed by a west-northwestward motion through Thursday as Rene rounds the southwestern periphery of a deep-layer subtropical ridge. On days 4 ad 5, the cyclone is forecast to move more slowly northwestward to north-northwestward through a weakness in the aforementioned ridge. The track guidance appears to have stabilized on the latest set of model runs and, thus, the new NHC forecast track is very similar to the previous advisory track, and lies close to a blend of the TVCA and NOAA-HCCA consensus track models. The intensity forecast was held steady for the next 12 h or so until Rene clears the negative influence of the mountainous Cabo Verde Islands. It's possible that Rene could even weaken by the time it passes the western Cabo Verde Islands. Thereafter, however, environmental conditions appear conducive for the cyclone to gradually strengthen, becoming a hurricane on day 3. By days 4 and 5, an increase in southwesterly vertical wind shear is expected to induce a weakening trend. The new NHC intensity forecast is similar to a blend of the IVCN and the HCCA intensity consensus models, and the GFS model. Key Messages: 1. Rene is expected to produce tropical storm conditions across portions of the Cabo Verde Islands this morning and afternoon. A Tropical Storm Warning is in effect for those islands. 2. Rene will bring locally heavy rainfall to portions of the Cabo Verde Islands through this afternoon. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 16.2N 23.5W 35 KT 40 MPH 12H 08/1200Z 16.5N 25.5W 35 KT 40 MPH 24H 09/0000Z 16.8N 28.2W 45 KT 50 MPH 36H 09/1200Z 17.3N 30.9W 50 KT 60 MPH 48H 10/0000Z 18.2N 33.6W 60 KT 70 MPH 60H 10/1200Z 19.1N 36.1W 65 KT 75 MPH 72H 11/0000Z 20.2N 38.3W 70 KT 80 MPH 96H 12/0000Z 23.1N 41.9W 65 KT 75 MPH 120H 13/0000Z 27.6N 44.1W 55 KT 65 MPH $$ Forecaster Stewart
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