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Tropical Storm Kevin Discussion Number 16
NWS National Hurricane Center Miami FL EP112021
200 AM PDT Wed Aug 11 2021
The satellite presentation has degraded during the past several
hours and consists of an ill-defined surface circulation with an
associated ragged looking curved band in the south semi-circle.
The initial intensity is lowered to 40 kt for this advisory and is
based on a blend of the Dvorak satellite intensity estimates from
TAFB and SAB.
Statistical-dynamical SHIPS (GFS and ECMWF) intensity guidance show
the moderate northeasterly shear persisting, and as a result,
displacing the deep convective mass from the surface center for
another 24-36 hours. Later today, Kevin should begin moving over
decreasing (sub-26C) sea surface temperatures, and by mid-period,
entering a more statically stable and drier surrounding environment.
Therefore, steady weakening is forecast through the remaining
period, and Kevin is expected to become a depression tonight, and
degenerate into a remnant low by Thursday night. The NHC intensity
forecast is basically an update of the previous one, but now shows
the cyclone opening up into a trough of low pressure a little
sooner, similar to the global model solutions.
Kevin's surface center has been difficult to find this morning.
A timely SSMI/S microwave overpass, however, indicated that initial
position was a little south than previously noted, and the initial
motion is estimated to be northwestward, or 315/8 kt. Kevin is
being steered by a mid-tropospheric ridge to the northeast of the
cyclone and either a northwestward or west-northwestward motion is
forecast during the next 4 days. The official track forecast has
been nudged a bit to the left of the previous advisory, due to the
position adjustment, and is in agreement with the better performing
HCCA and TVCN multi-model consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 11/0900Z 19.8N 116.4W 40 KT 45 MPH
12H 11/1800Z 20.7N 117.5W 35 KT 40 MPH
24H 12/0600Z 22.1N 119.6W 30 KT 35 MPH
36H 12/1800Z 23.3N 121.6W 30 KT 35 MPH
48H 13/0600Z 24.5N 123.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 13/1800Z 25.6N 126.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 14/0600Z 27.0N 127.8W 20 KT 25 MPH...POST-TROP/REMNT LOW