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Tropical Storm Fernanda Discussion Number   5
NWS National Hurricane Center Miami FL       EP062017
900 PM MDT Wed Jul 12 2017

Recent microwave images show that the center of Fernanda remains
near the northeastern edge of the deep convection due to light-to-
moderate northeasterly shear. However, the center has become a
little more embedded within the cold cloud tops this evening.  As a
result of the slight improvement in organization, the initial wind
speed has been increased to 40 kt. The global models show the shear
over Fernanda decreasing within the next 12 to 24 h and becoming
quite low while the cyclone moves over warm water during the
remainder of the forecast period.  This should lead to strengthening
and most of the intensity guidance brings Fernanda to major
hurricane strength in 3 to 4 days.  The updated NHC forecast is
slightly higher than the previous advisory and also shows Fernanda
becoming a major hurricane.  It should be noted that the SHIPS
Rapid Intensity Index shows a 50 percent chance of a 65 kt increase
in intensity over the next 3 days.

Fernanda is moving westward to west-southwestward at about 8 kt.  A
deep layer ridge to the north of the cyclone is forecast to build
westward during the next few days which should keep Fernanda on a
west or slightly south-of-west heading.  After 72 h, the tropical
cyclone is forecast to turn west-northwestward as it nears the
western portion of the ridge.  The track guidance is in good
agreement through 72 hours, but there are some differences in the
forward speed of the cyclone and how much latitude it will gain
later in the period.  The NHC track is similar to the previous
advisory and lies along the southern edge of the guidance envelope
at days 4 and 5. This is in best agreement with the ECMWF and
the HFIP corrected consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  13/0300Z 11.9N 113.1W   40 KT  45 MPH
 12H  13/1200Z 11.9N 114.5W   50 KT  60 MPH
 24H  14/0000Z 11.7N 116.5W   60 KT  70 MPH
 36H  14/1200Z 11.5N 118.5W   70 KT  80 MPH
 48H  15/0000Z 11.4N 120.6W   80 KT  90 MPH
 72H  16/0000Z 11.7N 125.1W   95 KT 110 MPH
 96H  17/0000Z 12.5N 129.5W  100 KT 115 MPH
120H  18/0000Z 13.5N 133.5W  100 KT 115 MPH

$$
Forecaster Brown

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