Hurricane Leslie Discussion Number  21
NWS National Hurricane Center Miami FL       AL132024
1100 AM AST Mon Oct 07 2024

Leslie appears slightly less organized based on infrared and visible 
satellite imagery.  However, an SSMIS microwave pass from a few 
hours ago indicated that there was still a feature resembling an eye 
on the 91-GHz imagery.  Subjective Dvorak estimates from TAFB and 
SAB are T-4.5/77 kt.  The objective estimates from UW-CIMSS range 
from 65 to 84 kt.  The initial intensity is nudged down slightly to 
75 kt, based on the degraded satellite presentation noted on 
conventional satellite imagery.

Leslie is moving northwestward, or 315/11 kt.  Leslie is expected to 
move around the southwestern periphery of a subtropical ridge to the 
northeast of the cyclone and turn gradually north-northwestward to 
northward toward the end of the week.  The NHC track forecast was 
nudged only slightly to the right of the previous official forecast 
during the first 72 h of the forecast and is close to the various 
track consensus aids.

Leslie will remain over warm ocean water through the 5-day forecast 
period, and it will remain in an environment of relatively low 
vertical wind shear for another 48 h.  However, dry air in the 
lower and middle troposphere should prevent any strengthening.  In 
fact, the bulk of the intensity guidance shows weakening, and the 
NHC forecast follows suit.  Due to Leslie's small size, its core 
seems to be vulnerable to the dry air, despite the low shear.  Only 
minor changes are made to the official intensity forecast, which 
lies near the lower end of the intensity guidance.  Beyond 48 h, 
Leslie is forecast to run into strong northerly wind shear as the 
cyclone interacts with an upper-level trough.  This shear will 
cause continued weakening.  Simulated satellite imagery is showing 
Leslie losing its convection beyond day 4, and the NHC forecast 
shows the tropical cyclone becoming post-tropical in 4 to 5 days.


FORECAST POSITIONS AND MAX WINDS

INIT  07/1500Z 16.4N  41.2W   75 KT  85 MPH
12H  08/0000Z 17.5N  42.5W   65 KT  75 MPH
24H  08/1200Z 19.0N  44.2W   60 KT  70 MPH
36H  09/0000Z 20.5N  45.9W   55 KT  65 MPH
48H  09/1200Z 21.6N  47.2W   55 KT  65 MPH
60H  10/0000Z 22.4N  48.3W   50 KT  60 MPH
72H  10/1200Z 23.1N  49.1W   45 KT  50 MPH
96H  11/1200Z 24.7N  50.0W   40 KT  45 MPH
120H  12/1200Z 27.0N  48.9W   35 KT  40 MPH...POST-TROPICAL

$$
Forecaster Hagen