[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 100243
TCDAT5

TROPICAL STORM NICOLE DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
1100 PM AST SUN OCT 09 2016

Depp convection associated with Nicole has decreased since the last
advisory, with the primary convection now confined to an area south
of the center.  It is unclear whether this is due to the normal
diurnal convective minimum, entrainment of dry air seen near the
center in water vapor imagery, or the result of cooling sea surface
temperatures under the stationary storm.  Satellite intensity
estimates from TAFB and SAB remain 55 kt, while the latest satellite
consensus estimate from CIMSS is 51 kt. Based on these data, the
initial intensity remains 55 kt.

Nicole is now drifting northward, and this motion should continue
for the next 12-24 hours as a blocking ridge of high pressure north
of the cyclone weakens.  A deep-layer trough associated with former
Hurricane Matthew is forecast to pass north of Nicole, with a second
ridge passing north of the storm after 24 hours.  This should cause
a northwestward turn, and the guidance during this stage of the
forecast has shifted left since the previous advisory.  After 72
hours, a new trough moving eastward from the United States should
cause Nicole to recurve northeastward into the westerlies.  The new
forecast track is shifted to the left between 24-72 hours, but still
lies to the east of the various consensus models.  After 72 hours,
the track lies a little north of the previous track.

A combination of the above mentioned dry air, possible cooler
waters, and continuing strong northerly shear should limit
intensification for the next 12 hours or so.  After that, the shear
should gradually subside and allow Nicole to intensify if the
cyclone does not entrain too much low-level dry air brought
southward due to Matthew.  The environment is most favorable at
about 72 hours, and the new intensity forecast calls for a slightly
increased peak intensity of 85 kt in best agreement with the SHIPS
model.  After that time, the cyclone is expected to encounter the
mid-latitude westerlies with increased shear partly compensated for
by increased upper-level divergence. This environment should lead to
gradual weakening with extratropical transition beginning near 120
hours.





FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 24.4N  65.3W   55 KT  65 MPH
 12H  10/1200Z 25.1N  65.3W   55 KT  65 MPH
 24H  11/0000Z 26.0N  65.5W   60 KT  70 MPH
 36H  11/1200Z 26.6N  65.9W   65 KT  75 MPH
 48H  12/0000Z 27.1N  66.4W   70 KT  80 MPH
 72H  13/0000Z 28.5N  66.5W   85 KT 100 MPH
 96H  14/0000Z 32.0N  64.0W   85 KT 100 MPH
120H  15/0000Z 37.0N  58.0W   70 KT  80 MPH

$$
Forecaster Beven

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