Hurricane Leslie Discussion Number  30
NWS National Hurricane Center Miami FL       AL132024
500 PM AST Wed Oct 09 2024

Leslie continues to take advantage of the little time it has left 
under favorable environmental conditions.  Although an eye is not 
currently seen on visible or infrared imagery, a 1611 UTC AMSR2 
image shows that an eye exists on microwave imagery, and it is 
located underneath the middle of the central dense overcast.  
Subjective Dvorak numbers from TAFB and SAB are a unanimous T-4.5/77 
kt, whereas recent objective intensity estimates from UW-CIMSS have 
been averaging in the 78-85 kt range for the past several hours.  
The initial intensity is bumped up to 80 kt, using a blend of the 
subjective and objective estimates.

Leslie's initial motion estimate is northwestward, or 310/8 kt. 
There has been no change to the track forecast reasoning.  Leslie is 
expected to turn northward in 24-36 h as it rounds the southwestern 
and western periphery of a subtropical ridge to the east.  
Afterward, Leslie should accelerate toward the northeast in response 
to a strong trough approaching the cyclone from the northwest.  The 
guidance is a bit farther west this cycle, and the new NHC forecast 
has shifted west of the previous one.

Saildrone data from the last several hours indicates that Leslie is 
over sea-surface temperatures approximately 1 to 2 degrees warmer 
than other data sources are indicating, and this could be the main 
reason why Leslie has strengthened a bit more than anticipated over 
the past 12 to 24 h.  A bit more strengthening is forecast during 
the next 12 h while the vertical wind shear remains relatively 
low.  In about 12 to 18 h, Leslie is expected to run into a wall of 
strong northerly shear caused by a strengthening upper-level 
anticyclone in between Milton and Leslie.  The shear is expected to 
cause Leslie to rapidly weaken during the 24 to 48 h period.  While 
it is possible that Leslie could lose most of its convection in 2 to 
3 days, the latest GFS and ECMWF simulated satellite imagery now 
show several periodic bursts of convection continuing into Day 4.  
Leslie might also merge with a front and become extratropical in 3 
to 4 days.  Regardless, Leslie will be traveling over much colder 
water by that time, and the official forecast calls for Leslie to 
become post-tropical in 3 to 4 days.


FORECAST POSITIONS AND MAX WINDS

INIT  09/2100Z 22.2N  49.0W   80 KT  90 MPH
12H  10/0600Z 22.9N  49.7W   85 KT 100 MPH
24H  10/1800Z 23.8N  50.4W   80 KT  90 MPH
36H  11/0600Z 25.3N  50.5W   60 KT  70 MPH
48H  11/1800Z 27.2N  49.4W   50 KT  60 MPH
60H  12/0600Z 29.7N  47.0W   45 KT  50 MPH
72H  12/1800Z 31.9N  43.2W   45 KT  50 MPH
96H  13/1800Z 35.4N  33.4W   45 KT  50 MPH...POST-TROPICAL
120H  14/1800Z 36.5N  25.2W   30 KT  35 MPH...POST-TROPICAL

$$
Forecaster Hagen