[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 081438
TCDAT5

TROPICAL STORM NICOLE DISCUSSION NUMBER  18
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL152016
1100 AM AST SAT OCT 08 2016

Nicole's cloud pattern has further deteriorated this morning.  The
low-level center has been exposed, with generally only shallow
convection on the southern and eastern periphery of the cyclone's
circulation.  A new burst of deeper convection has developed
southeast of the center in the last couple of hours, however. Dvorak
Final-T numbers continue to decrease, and a blend of those data and
CI-numbers support lowering the initial intensity estimate to 35 kt.

Nicole is moving just west of due south or 190/06.  A blocking high
north of the cyclone should continue to push it southward for about
24 hours. Nicole should then reverse its heading and turn north-
northwestward, when the mid-level high shifts to its northeast.  A
potential complication to the track forecast is the degree to which
Nicole interacts with Matthew or its remnants, beginning in 2 to 3
days through the latter part of the forecast period.  The ECMWF
shows a stronger binary interaction and draws Nicole much farther
west than the GFS after 72 hours, and the differences in the models
by 96 hours become extreme. The track forecast philosophy continues
to closely follow a blend of the ECMWF and GFS model solutions,
though slightly more weight has been placed on the GFS-based
guidance since a sizable number of ECMWF ensemble members are east
of its deterministic run. Admittedly, the forecast on days 4 and 5
are of low confidence.

The shear is forecast to be so strong in the short term that one
might be tempted to call for Nicole to degenerate to a remnant low,
especially given its current satellite appearance.  However, the
shear is forecast to nominally decrease, when the tail of a mid-
to upper-level trough over the central Atlantic fractures and
becomes co-located with the tropical cyclone during the next day
or so. How the merger of the two affects Nicole's intensity
and structure remains unclear.  Nonetheless, the large-scale
conditions are shown to become less hostile in 2 to 4 days, and it
seems plausible that some re-intensification of the cyclone could
occur before becoming less favorable again by day 5.  The new
intensity forecast is somewhat lower than the previous one and below
the multi-model consensus, and continues to show a modest recovery
after 72 hours.  The intensity forecast continues to be of low
confidence in the long range.


FORECAST POSITIONS AND MAX WINDS

INIT  08/1500Z 25.2N  65.7W   35 KT  40 MPH
 12H  09/0000Z 24.6N  65.7W   35 KT  40 MPH
 24H  09/1200Z 24.2N  65.8W   35 KT  40 MPH
 36H  10/0000Z 24.8N  65.9W   35 KT  40 MPH
 48H  10/1200Z 25.7N  66.0W   35 KT  40 MPH
 72H  11/1200Z 28.3N  66.6W   40 KT  45 MPH
 96H  12/1200Z 30.5N  67.0W   45 KT  50 MPH
120H  13/1200Z 33.4N  64.6W   45 KT  50 MPH

$$
Forecaster Kimberlain
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