762 
WTNT43 KNHC 302038
TCDAT3

Tropical Storm Leslie Discussion Number  18
NWS National Hurricane Center Miami FL       AL132018
500 PM AST Sun Sep 30 2018

Leslie has generally changed little in organization today.  The
tropical storm continues to produce deep convection in a band to
the southeast of the center, but there is a minimal amount of
shower activity elsewhere.  This asymmetric cloud pattern is due to
about 25 kt of northwesterly wind shear.  The initial intensity is
again held at 45 kt, but some of the satellite estimates suggest
that this could be a little generous.  The global models show the
upper-level pattern becoming more favorable over Leslie in about a
day, which combined with warmer SSTs should allow Leslie to
gradually strengthen during the next 2 to 3 days.  After that time,
the storm is expected to move northeastward back over its previous
track and cooler waters partly caused by its own upwelling.  These
conditions should end the strengthening trend and induce some
weakening.  The NHC intensity forecast is largely an update of the
previous one and in line with the IVCN, FSSE, and HCCA consensus
models.

Leslie is drifting to the southwest, with the latest initial motion
estimate being 240/4 kt.  The storm is forecast to remain in very
weak steering currents, and Leslie will likely drift southward to
southwestward during the next few days on the east side of a
mid-level ridge. Thereafter, a developing trough to the southwest of
Leslie should cause the system to move northeastward at a slightly
faster pace.  The models continue to shift back and forth each
cycle, which is not surprising given the weak steering.  This
forecast is adjusted a little to the left of the previous one to
come into better agreement with the latest models.  The bottom line
is that Leslie is forecast to meander over the central Atlantic for
the next several days.

Large swells generated by Leslie when it was a strong extratropical
low will continue to affect the east coast of the United States and
most of the Greater and Lesser Antilles for another day or two.
These swells could cause life-threatening surf and rip currents.
Although the swells will diminish some by mid-week, they will likely
remain hazardous for the same locations through the forecast period
due to Leslie's slow motion.

FORECAST POSITIONS AND MAX WINDS

INIT  30/2100Z 33.5N  53.2W   45 KT  50 MPH
 12H  01/0600Z 33.3N  53.7W   50 KT  60 MPH
 24H  01/1800Z 32.9N  54.3W   55 KT  65 MPH
 36H  02/0600Z 32.1N  55.0W   60 KT  70 MPH
 48H  02/1800Z 31.3N  55.3W   65 KT  75 MPH
 72H  03/1800Z 31.0N  54.7W   65 KT  75 MPH
 96H  04/1800Z 33.5N  53.5W   60 KT  70 MPH
120H  05/1800Z 36.5N  52.0W   60 KT  70 MPH

$$
Forecaster Cangialosi