[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 060241
TCDAT5

TROPICAL STORM NICOLE DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
1100 PM AST WED OCT 05 2016

Nicole has continued to become better organized during the past
several hours with a warm spot appearing on the night visible
images.  The latest microwave data also show that the storm has
maintained a mid-level eye, although the eye still isn't very well-
defined in the low-level channels.  Subjective Dvorak estimates
range from 55 to 65 kt, so the initial intensity is raised to 60 kt.

The storm is starting to take on a more asymetric appearance, a sign
that the long-awaited shear might finally be starting to impact the
cyclone. Still, the shear is not forecast to increase much over the
next day or so, and Nicole has the opportunity to strengthen into a
hurricane during that time, although not explicitly forecast below.
Vertical wind shear should become rather strong by the end of the
forecast period, and Nicole's winds should gradually decrease by
early next week.  It is a little puzzling that, with such strong
shear in all of the global models, a lot of guidance don't show much
weakening. Given the likelihood of such an unfavorable environment,
the latest official forecast is very similar to the previous one, on
the low side of the guidance closest to the LGEM model.

The initial motion has turned to the right, now 320/8.  Most of the
guidance move the system to the north-northwest or north at a
decreasing forward speed over the next 36 hours as a ridge collapses
to the north of Nicole.  After that time, northerly flow related to
a trough over the central Atlantic is forecast to steer Nicole
slowly southward for a couple of days.  Up to about 72 hours, the
model guidance is in reasonable agreement on this solution.
Thereafter, the model spread becomes increasingly large very
quickly, with a massive 1000 mile spread between the HWRF and the
ECMWF models by day 5.  This appears to be related to Nicole's
possible interaction with Matthew and/or the southern portion of the
trough, resulting in tracks primarily toward the southwest, west, or
northeast.  The latest long-range NHC forecast is very close to a
blend of the GFS, UKMET and ECMWF ensemble means, with more weight
on the ECMWF solution.  This forecast shows a slow northward motion
by the end of the period, ending up pretty close to the previous
NHC prediction.


FORECAST POSITIONS AND MAX WINDS

INIT  06/0300Z 26.0N  64.1W   60 KT  70 MPH
 12H  06/1200Z 26.9N  64.8W   60 KT  70 MPH
 24H  07/0000Z 27.7N  65.3W   60 KT  70 MPH
 36H  07/1200Z 27.8N  65.2W   55 KT  65 MPH
 48H  08/0000Z 27.5N  64.5W   55 KT  65 MPH
 72H  09/0000Z 26.5N  64.5W   55 KT  65 MPH
 96H  10/0000Z 27.5N  65.5W   45 KT  50 MPH
120H  11/0000Z 29.0N  65.5W   35 KT  40 MPH

$$
Forecaster Blake

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