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TROPICAL STORM KEVIN DISCUSSION NUMBER  17
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP142015
200 PM PDT FRI SEP 04 2015

Kevin is weakening. Its circulation center is on the southern edge
of large circular mass of deep convection that the cyclone has
maintained since overnight. A sequence of microwave images shows a
gradual dislocation of low- to mid-level centers, evidence that
south-southwesterly shear is taking its toll. Dvorak intensity
estimates are gradually decreasing, and a blend of these data is
used to lower the intensity to 45 kt.

Quick weakening is likely to continue.  A mid- to upper-level trough
impinging on Kevin from the west should produce even stronger shear
soon, and global models depict a decoupling of the cyclone in 12
hours or less.  Much drier mid- to upper-tropospheric air associated
with the trough should also reach Kevin's circulation and result in
a collapse of deep convection during the next day or so. The new
intensity forecast calls for a rapid decline, with remnant
low status by 36 hours and dissipation by 3 days.

Kevin has been moving due northward, and the initial motion estimate
is 360/07.  This general motion is expected until the cyclone fully
decouples on Saturday.  After that time, the shallower cyclone
should gain a greater westerly component of motion as it meets the
opposing flow around the low-level subtropical ridge over the
eastern Pacific.  The new track forecast is adjusted to the right
again due to a delay in the north-northwestward motion forecast in
previous model runs to have begun by now.


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 22.0N 115.2W   45 KT  50 MPH
 12H  05/0600Z 22.8N 115.4W   40 KT  45 MPH
 24H  05/1800Z 23.4N 116.1W   30 KT  35 MPH
 36H  06/0600Z 23.7N 117.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  06/1800Z 23.6N 118.6W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  07/1800Z...DISSIPATED

$$
Forecaster Kimberlain

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