[Tropical] Tropical Cyclone Discussion

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WTNT43 KNHC 070848
TCDAT3

Tropical Storm Leslie Discussion Number  44
NWS National Hurricane Center Miami FL       AL132018
500 AM AST Sun Oct 07 2018

Leslie has not changed much overnight.  The storm has several curved
bands to the east and north of the center, but a limited amount
of deep convection in the southwestern quadrant.  The initial
intensity is held at 50 kt based on the steady state appearance
since the previous ASCAT pass. This estimate is also in fair
agreement with the latest Dvorak estimates from TAFB and SAB.
Leslie will likely fluctuate in strength during the next several
days, but it should remain a tropical storm through the forecast
period. Although some weakening is possible during the next day or
so due to cool 23 to 24 deg C waters, slight re-strengthening is
likely after that time when the system moves back over warmer waters
and remains in relatively low wind shear conditions.  There could be
some increase in shear by the end of the forecast period, however,
which could result in slight weakening again.  The models are in
fairly good agreement, and the NHC intensity forecast is close to
the IVCN and HCCA consensus models.

Leslie is moving eastward at 10 kt within the mid-latitude westerly
flow on the south side of a broad mid- to upper-level trough.  This
trough is expected to amplify some, which should cause the storm to
move east-southeastward at a faster pace during the next few days.
A slight turn back to the east or east-northeast with a decrease
in forward speed is likely by the end of the forecast period when
the trough weakens.   There is a significant amount of spread in
the models associated with differences on how fast they expect
Leslie to move.  In fact, the GFS and ECMWF models are more than
1000 n mi apart by day 5.  The NHC track forecast is a little slower
than the previous one at the end of the period to come in better
agreement with the latest consensus aids.  Given the model spread,
the confidence in the long-range track forecast is low at this
time.

Large swells generated by Leslie are expected to continue through
tonight across the northeastern coast of the United States, Bermuda,
the Greater and Lesser Antilles, and Atlantic Canada. Please
consult products from your local weather office as these conditions
could cause life-threatening surf and rip currents.


FORECAST POSITIONS AND MAX WINDS

INIT  07/0900Z 37.2N  52.0W   50 KT  60 MPH
 12H  07/1800Z 36.6N  50.3W   45 KT  50 MPH
 24H  08/0600Z 36.1N  48.0W   45 KT  50 MPH
 36H  08/1800Z 35.1N  45.1W   50 KT  60 MPH
 48H  09/0600Z 33.7N  42.2W   55 KT  65 MPH
 72H  10/0600Z 30.1N  36.0W   55 KT  65 MPH
 96H  11/0600Z 28.6N  32.0W   55 KT  65 MPH
120H  12/0600Z 29.5N  27.2W   50 KT  60 MPH

$$
Forecaster Cangialosi
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