Hurricane Leslie Forecast Discussion Number 56

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000
WTNT43 KNHC 100834
TCDAT3

Hurricane Leslie Discussion Number  56
NWS National Hurricane Center Miami FL       AL132018
500 AM AST Wed Oct 10 2018

Geostationary satellite and microwave images indicate that Leslie
has a large and ragged banded eye feature with deep convection most
organized over the northern semicircle.  Since the Dvorak
classifications from TAFB and SAB are unchanged at 4.0/65 kt, the
initial wind speed is held at that value.  Leslie has another day or
two to strengthen while it remains in low wind shear conditions and
over marginally warm waters.  After that time, an increase in shear
and lower SSTs should cause Leslie to weaken. It is possible that
Leslie could become a post-tropical cyclone by day 5, but confidence
is not high on that occurring.  The NHC intensity forecast is
largely an update of the previous one and it lies at the high end of
the model guidance.

Leslie is now moving southward at 9 kt in the flow on the southwest
side of a broad mid- to upper-level trough.  A slower south-
southeastward motion is expected during the day today as the
trough pulls away.  A turn to the east-northeast is expected tonight
as another trough approaches Leslie from the northwest, and that
motion with an increase in forward speed is expected through early
this weekend.  After that time, the models are coming into better
agreement in showing Leslie being left behind and moving
southwestward on Sunday and Monday as a ridge builds to its
northwest.  The NHC track forecast is adjusted southward at days 3
to 5 to be closer to the latest consensus aids.  Although the
deterministic models are in better agreement this cycle, there is
still a lot of spread in the GFS and ECMWF ensemble members and
confidence in the track forecast remains fairly low.

FORECAST POSITIONS AND MAX WINDS

INIT  10/0900Z 28.6N  42.6W   65 KT  75 MPH
 12H  10/1800Z 28.0N  42.3W   70 KT  80 MPH
 24H  11/0600Z 28.1N  40.9W   75 KT  85 MPH
 36H  11/1800Z 29.1N  38.3W   80 KT  90 MPH
 48H  12/0600Z 30.5N  34.2W   75 KT  85 MPH
 72H  13/0600Z 31.5N  25.0W   70 KT  80 MPH
 96H  14/0600Z 30.5N  21.5W   50 KT  60 MPH
120H  15/0600Z 28.5N  23.5W   40 KT  45 MPH

$$
Forecaster Cangialosi