Hurricane Leslie Discussion Number  27
NWS National Hurricane Center Miami FL       AL132024
1100 PM AST Tue Oct 08 2024

This evening, Leslie's structure has improved further as deep 
convection can be seen wrapping around the center on GOES-16 
infrared imagery. An earlier ISS-COWVR microwave pass at 2021 UTC 
also showed a small inner-core eyewall feature. Subjective Dvorak 
fixes from TAFB and SAB were both T4.0/65-kt, but objective 
estimates from ADT and SATCON have jumped up to 79 and 74 kt 
respectively, and thus the initial intensity is raised to 70 kt, in 
between the subjective and objective estimates.

One thing that hasn't changed is Leslie's current motion, still off 
to the northwest at 310/10 kt. Over the next couple of days, Leslie 
will be approaching the westward extent of the subtropical ridge 
that has been its primary steering mechanism, resulting in a gradual 
slow down and turn northward by the end of this week. Leslie is then 
expected to be captured by an approaching long-wave trough, leading 
to a northeastward motion by the end of the forecast period. The NHC 
track continues to be in good agreement with the track guidance, and 
is just a touch west compared to the prior forecast.

Leslie's intensity prospects in the short-term have undergone a 
reversal from yesterday. The shear that had been affecting the 
hurricane has subsided, and SHIPS guidance now shows deep-layer 
shear reaming under 10 kt for at least the next 24 hours. Even 
though Leslie has been traveling over a cooler ocean left behind 
from Kirk last week, the sea-surface temperatures still appear to be 
warm enough (27-28 C) to promote intensification, as evidence of its 
continued deep convective bursts which have helped reform its inner 
core. The intensity guidance has responded to these changes by now 
showing more intensification. In fact, the raw 18 UTC HAFS-A/B runs 
now show intensification up to 80-85 kt in 36 hours. In addition, 
the latest ECMWF run, not usually known for being at the upper-end 
of the intensity guidance, shows significant deepening in the 
short-term, with a forecast pressure down to 969 mb by early 
Thursday morning. Based on these signals, the intensity guidance was 
raised upward significantly in the short term, and now shows Leslie 
peaking as an 80 kt hurricane in 24-36 hours. After that time, a 
large upper-level anticyclone approaching from the northwest 
(partially related to outflow from both AL93 and Milton) should lead 
to an abrupt increase in northerly shear. Thus, rapid weakening is 
still anticipated beyond that time, and Leslie still appears likely 
to become a post-tropical cyclone in about 3 days, as its convection 
is stripped away by the shear. The intensity forecast is on the 
upper-end of the guidance over the first 36 h, but falls back to the 
guidance mean by the end of the forecast period.


FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 20.7N  47.0W   70 KT  80 MPH
12H  09/1200Z 21.7N  48.0W   75 KT  85 MPH
24H  10/0000Z 22.7N  49.0W   80 KT  90 MPH
36H  10/1200Z 23.6N  49.7W   80 KT  90 MPH
48H  11/0000Z 24.8N  49.9W   60 KT  70 MPH
60H  11/1200Z 26.6N  49.1W   45 KT  50 MPH
72H  12/0000Z 29.0N  47.0W   40 KT  45 MPH...POST-TROPICAL
96H  13/0000Z 33.0N  39.5W   35 KT  40 MPH...POST-TROPICAL
120H  14/0000Z 35.1N  32.0W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin