[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 142037
TCDAT5

HURRICANE NICOLE DISCUSSION NUMBER  43
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
500 PM AST FRI OCT 14 2016

A few patches of disorganized deep convection have formed closer to
the center of Nicole, although the majority of the cloud pattern is
still comprised of low- to mid-level clouds and shallow convection.
Based on a satellite intensity estimate of 65 kt from TAFB and
earlier scatterometer data, the initial intensity is reduced to 65
kt.

The initial motion is 065/17.  There is no change in the track
forecast philosophy from the last advisory.   Nicole is embedded in
the mid-latitude westerlies to the southeast of a deep-layer trough
moving eastward through southeastern Canada.  The dynamical models
forecast the trough to bypass Nicole to the north after 24 hours,
which will weaken the steering flow and reduce Nicole's forward
speed during the 24-72 hour period.  Subsequently, a new mid-
latitude trough moving through southeastern Canada should steer
Nicole northeastward at a faster forward speed.  The guidance is
still tightly clustered through 72 hours, and this part of the
forecast track is an update of the previous track.  Beyond that
time, the guidance has again shifted northward, with the ECMWF in
particular being faster and farther to the north than its previous
run. Based on this, the latter part of the new forecast track is
again nudged northward.

The dynamical models remain in good agreement that Nicole should
interact with the mid-latitude trough starting in 12 hours or less,
with the models forecasting the winds to increase slightly and the
central pressure to fall to 940-950 mb by 36 hours.  As this occurs,
the cyclone is most likely to develop into a post-tropical cyclone
with a convection-less warm core secluded inside an encircling
cooler air mass.  However, an alternative scenario suggested by the
GFS and ECMWF models is that organized convection re-develops inside
the warm seclusion during the next 48-72 hours and allows Nicole to
maintain tropical cyclone characteristics over sea surface
temperatures of about 24C. The intensity forecast continues to call
for the cyclone to become post-tropical, but there is lower
confidence that this will happen than on the previous advisory. As
done before, the post-tropical portion of Nicole's intensity and
wind radii forecasts have been modified based on input from the NOAA
Ocean Prediction Center.

Swells from Nicole will affect Bermuda and portions of the U.S. east
coast and Atlantic Canada during the next couple of days.  By early
next week, wave models suggest that long-period swell from Nicole
will radiate outward and affect much of the North Atlantic basin.


FORECAST POSITIONS AND MAX WINDS

INIT  14/2100Z 36.5N  55.7W   65 KT  75 MPH
 12H  15/0600Z 37.5N  52.9W   70 KT  80 MPH
 24H  15/1800Z 38.3N  50.3W   70 KT  80 MPH...POST-TROPICAL
 36H  16/0600Z 38.5N  48.6W   70 KT  80 MPH...POST-TROPICAL
 48H  16/1800Z 38.7N  47.6W   65 KT  75 MPH...POST-TROPICAL
 72H  17/1800Z 40.5N  45.5W   65 KT  75 MPH...POST-TROPICAL
 96H  18/1800Z 47.0N  40.0W   60 KT  70 MPH...POST-TROPICAL
120H  19/1800Z 53.0N  36.0W   60 KT  70 MPH...POST-TROPICAL

$$
Forecaster Beven
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