[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 141443
TCDAT5

HURRICANE NICOLE DISCUSSION NUMBER  42
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
1100 AM AST FRI OCT 14 2016

Nicole continues to become less organized in satellite imagery,
with the main convective area now well removed from the center over
the northern semicircle and only shallow convection remaining near
the center.  The latest subjective intensity estimates from TAFB
and SAB are 77 and 55 kt respectively, and the latest CIMSS SATCON
estimate is 68 kt.  Based on these data and the decay of the cloud
pattern, the initial intensity is reduced to 70 kt.

The initial motion is 060/16.  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 or
so, 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
tightly clustered through 48-72 hours, and this part of the forecast
track is an update of the previous track.  Beyond that time, the
guidance has shifted northward, and the new forecast track is also
nudged northward.

The dynamical models are in good agreement that Nicole should
interact with the mid-latitude trough starting in the next 12-24
hours, with the models forecasting a central pressure below 950 mb
in about 36 hours.  As this occurs, the cyclone is expected to
develop into a post-tropical cyclone with the warm core secluded
inside an encircling cooler air mass.  The guidance suggests that
Nicole will not fully develop frontal features during the forecast
period, so the new intensity forecast calls for the system to
remain a powerful post-tropical cyclone through 120 hours.  The
post-tropical portion of Nicole's intensity and wind radii forecasts
have been modified based on input from the NOAA Ocean Prediction
Center.

Note that 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  14/1500Z 35.8N  58.0W   70 KT  80 MPH
 12H  15/0000Z 36.9N  55.0W   70 KT  80 MPH
 24H  15/1200Z 38.1N  51.7W   70 KT  80 MPH...POST-TROPICAL
 36H  16/0000Z 38.5N  49.6W   70 KT  80 MPH...POST-TROPICAL
 48H  16/1200Z 38.7N  48.2W   65 KT  75 MPH...POST-TROPICAL
 72H  17/1200Z 40.0N  46.0W   65 KT  75 MPH...POST-TROPICAL
 96H  18/1200Z 44.5N  42.0W   60 KT  70 MPH...POST-TROPICAL
120H  19/1200Z 51.0N  37.0W   55 KT  65 MPH...POST-TROPICAL

$$
Forecaster Beven
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