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TROPICAL STORM KEVIN DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP142015
200 PM PDT THU SEP 03 2015
The intensity and coverage of deep convection being produced by
Kevin has been decreasing, although this may be a diurnal
fluctuation. There are some ill-defined banding features over the
northern semicircle, and the cyclone still has some outflow over
the southern part of the circulation. The latter is a bit
surprising, given the south-southwesterly shear over the system.
The current intensity is held at 45 kt which is consistent with the
latest Dvorak estimate from TAFB. There is a narrow window of
opportunity for intensification in the short term, i.e. during the
next 12 to 24 hours. Thereafter, the shear is forecast to increase
and the cyclone should be ingesting drier and more stable air. The
official forecast shows slight strengthening overnight followed by
weakening and eventual degeneration into a remnant low in about 3
days. This is very close to the latest model consensus. Some of
the guidance, such as the SHIPS model, show an even faster weakening
than indicated here.
Recent microwave imagery has provided some good center fixes, and
the initial motion is a slightly faster 360/7. Kevin should move
northward to northwestward on the southwest side of a mid-level
subtropical anticyclone for the next day or two. Afterward, the
weakening and increasingly shallow cyclone is likely to turn toward
the west and be steered mainly by the low-level flow. The GFDL and
HWRF models show a much more northward track, and appear to be
unrealistic. The official track forecast is similar to the previous
one, and close to the latest ECMWF solution.
FORECAST POSITIONS AND MAX WINDS
INIT 03/2100Z 18.7N 115.8W 45 KT 50 MPH
12H 04/0600Z 19.8N 115.8W 50 KT 60 MPH
24H 04/1800Z 21.2N 115.8W 50 KT 60 MPH
36H 05/0600Z 22.0N 116.3W 45 KT 50 MPH
48H 05/1800Z 22.3N 117.1W 40 KT 45 MPH
72H 06/1800Z 22.5N 119.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 07/1800Z 22.5N 121.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 08/1800Z...DISSIPATED
$$
Forecaster Pasch
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