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Tropical Storm Leslie Discussion Number 19
NWS National Hurricane Center Miami FL AL132018
1100 PM AST Sun Sep 30 2018
Leslie has changed little in organization over the past few hours,
with the convective burst previously in the southeastern quadrant
now in the northeastern quadrant. Recent scatterometer data
indicates that the current intensity is 45 kt, with those winds
occurring in the northeastern semicircle. The scatterometer data
also suggests that the radii of tropical-storm force winds has
decreased a little. While Leslie continues to be affected by
westerly shear, the global models show the upper-level pattern
becoming more favorable over Leslie in about a day. This, combined
with slightly warmer SSTs along the forecast track 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,
and that should cause at least a little weakening. The new
intensity forecast is unchanged from the previous forecast, and it
lies above the forecast of the regional hurricane models and below
the forecast of the statistical-dynamical models.
The initial motion is 250/5. Leslie is forecast to remain in weak
steering currents for the next 72 h, with a southwestward to
southward drift expected. Thereafter, a shortwave trough moving
southward to the west of Leslie should cause a motion toward the
north-northeast or northeast and an increase in forward speed.
There are no important changes to the guidance or to the forecast
track, and the bottom line remains 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 01/0300Z 33.3N 53.7W 45 KT 50 MPH
12H 01/1200Z 33.0N 54.2W 50 KT 60 MPH
24H 02/0000Z 32.4N 54.9W 55 KT 65 MPH
36H 02/1200Z 31.5N 55.5W 60 KT 70 MPH
48H 03/0000Z 30.8N 55.6W 65 KT 75 MPH
72H 04/0000Z 31.0N 55.0W 65 KT 75 MPH
96H 05/0000Z 34.0N 54.0W 60 KT 70 MPH
120H 06/0000Z 37.0N 52.5W 60 KT 70 MPH