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Tropical Storm Kenneth Discussion Number 3
NWS National Hurricane Center Miami FL EP132017
800 PM PDT Fri Aug 18 2017
Conventional satellite imagery and an earlier SSMI/S overpass show
that the depression has been strengthening during the past several
hours. Impressive outer curved banding has developed in the eastern
and northern portions of the cyclone, and the last few visible
images are showing early signs of a small central dense overcast, or
inner core formation. Based on the overall improvement of the cloud
pattern and Dvorak satellite intensity estimates of 35 kt from
SAB and TAFB, the depression is upgraded to Tropical Storm Kenneth.
The northeasterly shear is diminishing, the oceanic temperatures are
warm, and the low to mid levels of the atmosphere are moist, all
bolstering further strengthening through the 48-hour period.
Afterward, decreasing sea surface temperatures and an intruding
stable air mass from the north should result in gradual weakening.
No significant changes were made to the previous intensity forecast,
and the NHC forecast is based primarily on the IVCN multi-model
consensus.
The initial motion is estimated to be westward, or 280/13 kt.
Kenneth is embedded in the easterly mid-level flow of a subtropical
ridge extending over the eastern Pacific from northern Mexico. The
cyclone should commence a gradual turn toward the west-northwest
around the 24-hour period as a mid- to upper-level low located
just southwest of the southern California coast amplifies and
erodes the ridge to the northwest of Kenneth. Kenneth's motion is
expected to be further influenced by this growing weakness in the
ridge by decreasing in forward speed, turning northwestward on
day 3, and then north-northwestward around the 96-hour period. The
guidance suite is surprisingly tightly clustered through the entire
forecast period. The NHC track forecast is similar to the previous
one, and is hedged toward the HCCA corrected consensus model.
FORECAST POSITIONS AND MAX WINDS
INIT 19/0300Z 15.0N 119.1W 35 KT 40 MPH
12H 19/1200Z 15.4N 121.2W 45 KT 50 MPH
24H 20/0000Z 16.0N 124.1W 55 KT 65 MPH
36H 20/1200Z 16.8N 126.7W 65 KT 75 MPH
48H 21/0000Z 17.7N 128.9W 75 KT 85 MPH
72H 22/0000Z 19.6N 131.8W 70 KT 80 MPH
96H 23/0000Z 22.3N 133.1W 60 KT 70 MPH
120H 24/0000Z 25.2N 133.9W 45 KT 50 MPH
$$
Forecaster Roberts
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