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TROPICAL STORM FAY DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072014
500 PM AST SAT OCT 11 2014

Tropical Storm Fay remains a sheared tropical cyclone with deep
convection persisting in the northwestern quadrant. A 1442 UTC
ASCAT-B overpass indicated several 50-52 kt surface wind vectors in
the northeastern and northwestern quadrants, and buoy 41936 measured
a pressure of 990.2 mb a few hours ago when the center passed just
to its west. The initial intensity is being maintained at 60 kt for
this advisory given that the buoy pressure was similar to the last
recon reported surface pressure, and assuming that there is some
undersampling by the ASCAT instrument. An Air Force Reserve
reconnaissance aircraft is scheduled to investigate the cyclone
around 0000 UTC this evening.

The initial motion estimate is 360/16 kt, based in large part on
scatterometer and microwave satellite fixes. Fay is expected to
continue moving northward around a deep-layer ridge this evening,
and then turn toward the north-northeast by 0600 UTC, passing just
to the southeast of Bermuda at that time. However, only a slight
deviation to the west of the forecast track would bring the center
and core of strongest winds very close to or even over Bermuda, and
for that reason the Bermuda Weather Service has issued a hurricane
watch for the island. By 24 hours, Fay is expected to get caught up
in the mid-latitude westerlies and recurve rapidly to the northeast
or east-northeast before it merges with a frontal system by 48
hours. The new NHC guidance has again shifted a little to the left,
and the official forecast track has been shifted slightly westward
through 12 hours, and closely follows the multi-model consensus
TVCN.

Overall, there is no significant change to the previous intensity
forecast or reasoning. However, the current south-southeasterly
vertical wind shear of 32 kt is forecast by the GFS-based SHIPS
model to decrease to around 25 kt from the south-southwest in 12-18
hours, which could allow for some slight strengthening during the
convective maximum period around 0600 UTC tonight, and it is
possible that Fay could briefly reach hurricane status. After 24
hours, the wind shear is forecast to increase to more than 40 kt
from the southwest, which should induce a weakening trend up until
the time that Fay merges with a strong frontal system by 48 hours.

FORECAST POSITIONS AND MAX WINDS

INIT  11/2100Z 29.5N  65.4W   60 KT  70 MPH
 12H  12/0600Z 31.7N  64.4W   60 KT  70 MPH
 24H  12/1800Z 33.7N  61.2W   60 KT  70 MPH
 36H  13/0600Z 34.8N  56.2W   55 KT  65 MPH
 48H  13/1800Z...ABSORBED BY FRONTAL SYSTEM

$$
Forecaster Stewart

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