[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 302035
TCDAT1

TROPICAL STORM FRED DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL062015
500 PM AST SUN AUG 30 2015

Fred has continued to strengthen this afternoon.  A new burst of
deep convection has developed over the center, with the CDO becoming
more symmetric.  Late afternoon visible satellite pictures also
reveal increased banding in all quadrants.  AMSR-2 and GCOM
microwave data from late this morning indicated that Fred continues
to exhibit a well-defined inner core with a closed low-level ring in
the 37 GHz imagery.  The initial intensity has been raised to 55 kt,
which is in agreement with a subjective data T-number of 3.5 from
TAFB and T3.4 from UW/CIMSS ADT.

Fred is forecast to remain in a favorable environment characterized
by very low vertical wind shear, warm water, and sufficient
mid-level moisture during the next day or so.  Therefore, additional
strengthening is expected and the NHC forecast calls for Fred to
become a hurricane tonight or early Monday.  This is supported by
the statistical guidance and the HWRF model which bring Fred to
hurricane status.  In about 36 hours, the tropical cyclone
will be moving into a more hostile environment of increasing
southwesterly shear, cooler sea surface temperatures, and a more
stable air mass.  This should result in weakening throughout the
remainder of the forecast period, and the new NHC forecast weakens
Fred to a tropical depression by 120 h.

Fred has been moving faster than predicted today, and the initial
motion estimate is 310/14 kt.  The forecast track philosophy remains
unchanged from before.  The cyclone should move northwestward toward
a break in the subtropical ridge during the next day or so.  In a
couple of days, Fred should turn west-northwestward as the ridge
rebuilds to the north of the cyclone over the eastern and
central Atlantic.  The updated NHC track forecast is a little north
of the previous advisory after 48 hours to be in better agreement
with the GFEX (GFS and ECMWF) consensus model.

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  30/2100Z 14.4N  21.3W   55 KT  65 MPH
 12H  31/0600Z 15.6N  22.8W   65 KT  75 MPH
 24H  31/1800Z 16.9N  24.6W   70 KT  80 MPH
 36H  01/0600Z 18.2N  26.3W   65 KT  75 MPH
 48H  01/1800Z 19.2N  28.2W   60 KT  70 MPH
 72H  02/1800Z 20.6N  31.7W   50 KT  60 MPH
 96H  03/1800Z 21.8N  35.5W   40 KT  45 MPH
120H  04/1800Z 22.8N  39.0W   30 KT  35 MPH

$$
Forecaster Brown
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