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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.
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