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Tropical Storm Kevin Discussion Number 2
NWS National Hurricane Center Miami FL EP112021
300 PM MDT Sat Aug 07 2021
Visible satellite imagery has continued to show an improvement in
the cloud pattern of the tropical cyclone today. Banding has
increased over the western and southern portions of the circulation
while a small CDO has developed near the center. Scatterometer data
from around 1700 UTC revealed an area of 30-kt winds to the
northwest of the center, but with the continued increase in
organization and Dvorak T-numbers of T2.5 from both TAFB and SAB the
initial wind speed has been increased to 35 kt. Kevin becomes the
eleventh named storm in the eastern Pacific basin during the 2021
season, which is running about a month ahead of schedule as the
eleventh named storm typically does not form until early-to-mid
September.
Kevin is located within an environment of low-to-moderate shear,
warm sea surface temperatures, and a moist atmosphere. These
conditions are expected to support steady strengthening over the
next few days, and the cyclone is expected to become a hurricane
in about 36 hours. There is some spread in the intensity guidance
with the statistical guidance on the more aggressive side as
compared to some of the dynamical models. The NHC wind speed
forecast lies a little above the various consensus models but
slightly below the SHIPS guidance.
The storm is moving westward or 270/9 kt. A mid-tropospheric ridge
that extends across the subtropical eastern Pacific is forecast to
steer Kevin generally westward during the next 36 hours. After that
time, a cut-off low west of the Baja peninsula is expected to erode
the western portion of the ridge causing Kevin to turn west-
northwestward to northwestward through the remainder of the forecast
period. The GFS, which depicts an unrealistic elongation of the
system's low-level vorticity in about 48 hours, shows a much
sharper northward or northwestward motion from 48-72 hours. Less
weight was placed on that solution with the NHC track remaining
closer to the bulk of the guidance and the various consensus aids.
The latest track forecast is similar to, but a little slower than
previous advisory.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 15.8N 106.8W 35 KT 40 MPH
12H 08/0600Z 15.8N 108.1W 45 KT 50 MPH
24H 08/1800Z 15.7N 109.4W 55 KT 65 MPH
36H 09/0600Z 15.7N 110.5W 65 KT 75 MPH
48H 09/1800Z 16.2N 111.5W 70 KT 80 MPH
60H 10/0600Z 17.3N 112.7W 75 KT 85 MPH
72H 10/1800Z 18.2N 114.0W 75 KT 85 MPH
96H 11/1800Z 19.9N 117.6W 65 KT 75 MPH
120H 12/1800Z 21.9N 122.2W 50 KT 60 MPH
$$
Forecaster Brown
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