[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 101447
TCDAT5

TROPICAL STORM NICOLE DISCUSSION NUMBER  26
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
1100 AM AST MON OCT 10 2016

Nicole's cloud pattern has lost organization since late yesterday.
A series of convective bursts over the last 24 hours faded away into
a shallow and shapeless cloud mass earlier this morning.  Since
then, some deep convection has redeveloped over the low-level center
but there has been no apparent increase to its organization. A blend
of the Final-T and CI-number from the TAFB satellite classification
and UW-CIMSS ADT values are used to lower the initial intensity
estimate to 50 kt.

Nicole has been moving slowly northward or 360/05 as it moves
along the southwestern periphery of a mid-level ridge to its
northeast.  While this general motion should continue today, a
shortwave trough trekking across Atlantic Canada is expected to
bypass Nicole during the next 24 hours, and allow a weak mid-level
ridge to build north and west of the cyclone between 24 and 48
hours.  This synoptic pattern should result in a leftward bend of
the track through about 48 hours.  After that time, global models
show Nicole turning northward and then northeastward with an
increase in forward speed once it reaches a faster-paced westerly
flow around 30N.  Although the track guidance is in much better
agreement than it has been during the last few days, the theme from
yesterday of the ECMWF and its 0000 UTC ensemble members showing
Nicole with a greater westerly component from 24 to 72 hours
persists. In fact, a majority of the ECMWF ensembles members are
still, to varying degrees, left of the current forecast.  The new
track forecast is again adjusted to left of the previous one, closer
to the ECMWF, and is west of the model consensus aids.

During the last 24 hours, a piece of vorticity that fractured from
a central Atlantic shortwave trough has been merging with Nicole.
The interaction of this feature with Nicole and a continuation of
strong northerly shear could explain the degraded satellite
appearance of Nicole since yesterday.  Nonetheless, the shear
is still forecast to diminish during the next day or two, as the
cyclone traverses near-record warm SSTs, finds itself in a
reasonably moist environment and an increasingly diffluent flow
aloft.  These factors suggest that a significant re-intensification
is still possible, as the global models continue to show.  The only
caveat would be to what degree a drier and more stable air in the
wake of Post-Tropical Matthew would modify as it is at least
partially ingested by Nicole's circulation.  SHIPS model output
shows the shear greatly increasing by 96 hours, which would likely
result in an end to the predicted intensification phase unless
baroclinic processes become dominant and result in just a little bit
more.  The new intensity forecast is similar to the previous one and
is close to the multi-model consensus.  It should be noted that
global models show Nicole becoming a large hurricane in about 3
days, with a wide distribution of strong winds over the central
Atlantic.


FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 25.7N  65.2W   50 KT  60 MPH
 12H  11/0000Z 26.4N  65.4W   50 KT  60 MPH
 24H  11/1200Z 27.2N  66.0W   60 KT  70 MPH
 36H  12/0000Z 27.7N  66.5W   65 KT  75 MPH
 48H  12/1200Z 28.5N  66.8W   75 KT  85 MPH
 72H  13/1200Z 31.8N  65.2W   80 KT  90 MPH
 96H  14/1200Z 36.7N  59.6W   75 KT  85 MPH
120H  15/1200Z 41.2N  53.9W   70 KT  80 MPH...POST-TROP/EXTRATROP

$$
Forecaster Kimberlain

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