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Tropical Storm Kevin Discussion Number 11
NWS National Hurricane Center Miami FL EP112021
900 PM MDT Mon Aug 09 2021
Kevin remains a sheared tropical cyclone with most of the convection
displaced to the southwest of the elongated inner-core wind field
due to strong northeasterly vertical wind shear. However, some small
curved bands of shallow convection have recently developed in the
eastern semicircle, suggesting that the shear might be starting to
abate somewhat. The initial intensity has been decreased to 40 kt,
more in line with earlier ASCAT surface wind data that showed peak
surface winds near 40 kt.
The initial motion estimate remains west-northwestward, or 295/08
kt. There is no change to the previous track forecast reasoning.
Kevin is expected to continue moving west-northwestward through the
120-h forecast period along the southwestern periphery of a
deep-layer ridge. The new NHC track forecast is just a tad to the
right or north of the previous track, but remains near the southern
portion of the track model envelope, between the ECMWF model to the
south and the consensus models to the north.
Kevin is forecast remain under the influence of at least modest
northeasterly to easterly wind shear for the next 48 h. Thus little
change in strength is expected despite he warm sea-surface
temperatures (SST) exceeding 28C and a very moist mid-level
environment exceeding 80 percent relative humidity. Thereafter the
shear is forecast to decrease to less than 10 kt, which would
normally favor intensification. However, Kevin will be moving over
near-22 deg C SSTs at that time, so weakening rather than
strengthening is forecast in the 72-120 period. The latest official
intensity forecast is similar to the previous advisory, and closely
follows a blend of the consensus models HCCA and IVCN, and the Navy
COAMPS-TC model.
FORECAST POSITIONS AND MAX WINDS
INIT 10/0300Z 17.4N 112.9W 40 KT 45 MPH
12H 10/1200Z 18.1N 114.0W 40 KT 45 MPH
24H 11/0000Z 19.0N 115.3W 40 KT 45 MPH
36H 11/1200Z 20.0N 116.8W 40 KT 45 MPH
48H 12/0000Z 21.0N 118.6W 35 KT 40 MPH
60H 12/1200Z 21.8N 120.8W 30 KT 35 MPH
72H 13/0000Z 22.7N 123.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 14/0000Z 24.6N 127.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 15/0000Z 26.2N 132.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Stewart
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