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TROPICAL STORM KEVIN DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142015
800 PM PDT THU SEP 03 2015
Intense thunderstorms have been persisting near the center of Kevin
during the past several hours, with outflow continuing especially
in the cyclone's northern semicircle. Microwave data also show that
the inner core of the storm is better defined than earlier today.
The initial intensity is thus increased to 50 kt, a blend of the 45
kt classification from TAFB and the 55 kt one from SAB. The cyclone
should reach its peak intensity in the next 12 hours or so while the
shear remains low-to-moderate and waters are warm. Thereafter, the
shear is forecast to strengthen and Kevin will encounter more
marginal SSTs and dry mid-level air, which should cause weakening.
The official forecast is a blend of the previous forecast and the
intensity consensus. Degeneration into a remnant low in expected
about 3 days due to a continuation of the higher shear, low moisture
and cool water environment.
Kevin is moving a little faster tonight, estimated at 360/8. Over
the next day or so, while the system remains vertically intact, it
should move generally northward around the southwest side of a mid-
level ridge. Afterward, the weakening and increasingly shallow
cyclone is likely to turn toward the northwest and west and be
steered mainly by the low-level flow. Model guidance, however, is
not in good agreement on when this leftward turn will occur, with
almost all of the guidance delaying the turn a bit longer on this
cycle, resulting in Kevin gaining more latitude. Because Kevin has
now become a deeper cyclone, it makes sense to move the new NHC
prediction north of the previous one given that Kevin should now
take a little longer to become a more shallow cyclone. However, the
new forecast still lies south of most of the guidance and the model
consensus.
FORECAST POSITIONS AND MAX WINDS
INIT 04/0300Z 19.7N 115.8W 50 KT 60 MPH
12H 04/1200Z 20.8N 115.8W 50 KT 60 MPH
24H 05/0000Z 22.0N 115.9W 45 KT 50 MPH
36H 05/1200Z 22.7N 116.5W 40 KT 45 MPH
48H 06/0000Z 23.3N 117.3W 30 KT 35 MPH
72H 07/0000Z 23.5N 119.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 08/0000Z...DISSIPATED
$$
Forecaster Blake
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