[Tropical] Tropical Cyclone Discussion

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WTNT44 KNHC 270835
TCDAT4

Hurricane Lee Discussion Number  37
NWS National Hurricane Center Miami FL       AL142017
500 AM AST Wed Sep 27 2017

Conventional satellite imagery indicates that Lee has been
undergoing some cloud structural changes during the past several
hours.  The eye has nearly doubled in size to 30 miles in
diameter, the central pressure indicated in the CIMSS Objective
Dvorak technique has increased a few millibars, and an earlier 2147
UTC WindSAT overpass revealed a developing outer ring surrounding
the partially opened inner core. These aforementioned cloud pattern
alterations arguably point to an undergoing eyewall replacement
cycle, and the possibility of intensification in the short term.
The initial intensity of 95 kt remains above the subjective
T-numbers, and is close to the CIMSS ADT estimated intensity.  The
official intensity forecast reflects the possibility of Lee becoming
a major hurricane later today before a weakening trend commences by
early Wednesday.  The global models and the FSU Cyclone Phase
Evolution product agree that Lee will maintain tropical
characteristics through day 3.  Afterward, the guidance shows the
cyclone quickly absorbed by an existing larger baroclinic
system.

The initial motion is estimated to be west-northwestward, or 285/8
kt.  Lee should turn gradually northwestward later today, and
generally northward on Thursday as the cyclone is steered by the
southwestern peripheral flow of a subtropical ridge over the
east-central Atlantic.  Through the remaining portion of the
forecast, Lee is forecast to accelerate northeastward within the
strong mid-latitude southwesterly flow and ultimately dissipate in
72 hours.  The model guidance suite continues to trend toward the
west through the 36-hour period, and the official forecast follows
suit.  Beyond that time frame, the forecast is a little faster than
the previous advisory and is nudged toward the HFIP Corrected
Consensus technique model.


FORECAST POSITIONS AND MAX WINDS

INIT  27/0900Z 30.2N  56.3W   95 KT 110 MPH
 12H  27/1800Z 30.8N  57.0W   95 KT 110 MPH
 24H  28/0600Z 32.1N  57.3W   90 KT 105 MPH
 36H  28/1800Z 34.5N  56.5W   85 KT 100 MPH
 48H  29/0600Z 37.8N  53.1W   75 KT  85 MPH
 72H  30/0600Z 46.3N  39.0W   60 KT  70 MPH
 96H  01/0600Z...DISSIPATED

$$
Forecaster Roberts
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