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TROPICAL STORM FRED DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062015
1100 AM AST SUN AUG 30 2015
Visible satellite imagery indicates that convection associated
with the tropical cyclone continues to organize. A curved band of
convection now wraps almost completely around the center and recent
images show that a small CDO feature has developed. An earlier
WindSat microwave overpass also revealed a well-defined inner core.
Dvorak T-numbers from TAFB and UW/CIMSS are around 3.0, and based on
these the initial intensity is raised to 45 kt.
The environment ahead of Fred appears conducive for strengthening
during the next 24 to 36 hours. During that time, there will
be sufficient mid-level moisture, the shear is expected to remain
low, and the cyclone will be traversing sea surface temperatures
of 27 to 28C. Therefore, steady strengthening is anticipated and
the SHIPS and LGEM models bring Fred to hurricane status within
24 hours. Strengthening is also supported by the GFS and ECMWF
models, which both show the cyclone deepening while it moves through
the Cape Verde Islands. After 36 hours, lower sea surface
temperatures, increasing southwesterly shear, and a more stable
environment should cause weakening.
Fred is moving northwestward at about 11 kt. The tropical storm is
forecast to move northwestward toward a break in the subtropical
ridge to the north of the Cape Verde Islands. In a couple of days,
the ridge is forecast to build westward, which should cause Fred to
turn west-northwestward. As Fred weakens and become a more shallow
cyclone late in the period, a westward to west-northwestward
motion is expected. The NHC track is near the consensus of the
ECMWF and GFS models through 72 hours. Later in the period, the NHC
forecast shows a weaker system moving more westward, and this track
is along the southern edge of the guidance in best agreement with
the ECMWF.
Based on this track and intensity forecast, the Meteorological
Service of the Cape Verde Islands has issued a Hurricane Warning
for those islands.
Please note that the track/cone graphic, an automatically generated
product, does not have the capability of displaying warnings for the
Cape Verde Islands.
FORECAST POSITIONS AND MAX WINDS
INIT 30/1500Z 13.4N 19.9W 45 KT 50 MPH
12H 31/0000Z 14.3N 21.3W 55 KT 65 MPH
24H 31/1200Z 15.7N 23.1W 65 KT 75 MPH
36H 01/0000Z 17.2N 25.1W 65 KT 75 MPH
48H 01/1200Z 18.3N 27.1W 65 KT 75 MPH
72H 02/1200Z 19.5N 31.5W 55 KT 65 MPH
96H 03/1200Z 20.5N 35.5W 45 KT 50 MPH
120H 04/1200Z 21.0N 39.5W 40 KT 45 MPH
$$
Forecaster Brown
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