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Hurricane Fernanda Discussion Number  21
NWS National Hurricane Center Miami FL       EP062017
800 PM PDT Sun Jul 16 2017

Fernanda's eye has become less distinct, although the overall cloud
pattern remains quite symmetric and the central cloud tops have not
warmed significantly so far.  The current intensity is set to 105 kt
which is a blend of subjective Dvorak intensity estimates from TAFB
and SAB and ADT values from UW/CIMSS.  Sea surface temperatures
beneath the hurricane will should be slowly cooling over the next
few days and, later in the forecast period, west-southwesterly shear
is forecast to increase.  Therefore gradual weakening is forecast
during the next couple of days followed by a more rapid decline
thereafter.  The official intensity forecast is a little above the
model consensus through 48 hours and very close to it in 3-5 days.

The initial motion estimate, 290/10 kt, is not much different from
earlier today.  Fernanda is expected to approach the western
periphery of a mid-tropospheric ridge extending westward from the
United States.  This should cause the tropical cyclone to slow down
and turn a little to the right.  In 4-5 days the global models
show a ridge building to the north of Fernanda and this is likely
to cause a turn toward the west around that time.  The official
track forecast is similar to the previous one and lies between the
latest GFS and ECMWF solutions.

FORECAST POSITIONS AND MAX WINDS

INIT  17/0300Z 13.0N 129.2W  105 KT 120 MPH
 12H  17/1200Z 13.7N 130.6W  100 KT 115 MPH
 24H  18/0000Z 14.6N 132.1W   95 KT 110 MPH
 36H  18/1200Z 15.5N 133.4W   90 KT 105 MPH
 48H  19/0000Z 16.3N 134.6W   80 KT  90 MPH
 72H  20/0000Z 17.3N 137.3W   60 KT  70 MPH
 96H  21/0000Z 17.8N 140.7W   45 KT  50 MPH
120H  22/0000Z 18.3N 144.3W   35 KT  40 MPH

$$
Forecaster Pasch

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