[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 110244
TCDAT3

Tropical Storm Rene Discussion Number  16
NWS National Hurricane Center Miami FL       AL182020
1100 PM AST Thu Sep 10 2020

Microwave satellite images from late this afternoon and evening
shows that the center of Rene is located slightly northeast of the
main convective mass.  This appears to be due to some easterly flow
that is undercutting the outflow layer.  Dvorak CI numbers from
both SAB and TAFB remain 3.0 (45 kt) but the SAB T-number has
decreased slightly, and a recent ASCAT overpass suggests that the
winds are not as strong as previously estimated.  The ASCAT data
revealed peak winds of 30-35 kt, so the initial intensity has been
adjusted to 40 kt, which could be a little generous. The
upper-level wind pattern is expected to become favorable for
strengthening while the cyclone moves over marginally warm sea
surface temperatures during the next day or two.  This should allow
for some modest strengthening during that time, but the statistical
guidance is not as bullish as before.  Therefore the intensity
forecast has been lowered slightly, and if strengthening does not
occur soon additional downward adjustments to the intensity
prediction may be needed.  By 60 h, Rene is forecast to move into
an area of strong west-northwesterly shear, which is expected to
weaken the cyclone during the latter portion of the forecast
period.

Rene continues moving west-northwestward with a motion of 290/10
kt.  The cyclone is approaching the western periphery of a
mid-level ridge over the eastern Atlantic and Rene is forecast to
turn northwestward and then north-northwestward over the next few
days.  Later in the period, a ridge is forecast to build to the
northwest of the tropical cyclone and Rene's forward motion is
expected to slow considerably early next week.  There is a fair
amount of model spread by 96 and 120 h, with some of the global
models taking Rene more northeastward during that time.  The NHC
forecast continues to lie close to the various consensus aids, and
indicates a fairly slow forward speed on days 3-5.


FORECAST POSITIONS AND MAX WINDS

INIT  11/0300Z 19.3N  37.6W   40 KT  45 MPH
 12H  11/1200Z 19.8N  39.1W   45 KT  50 MPH
 24H  12/0000Z 20.7N  41.1W   50 KT  60 MPH
 36H  12/1200Z 22.0N  43.1W   55 KT  65 MPH
 48H  13/0000Z 23.7N  44.9W   60 KT  70 MPH
 60H  13/1200Z 25.2N  46.1W   60 KT  70 MPH
 72H  14/0000Z 26.4N  46.9W   55 KT  65 MPH
 96H  15/0000Z 27.3N  47.5W   45 KT  50 MPH
120H  16/0000Z 27.5N  49.7W   40 KT  45 MPH

$$
Forecaster Brown
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