Hurricane Leslie Discussion Number  31
NWS National Hurricane Center Miami FL       AL132024
1100 PM AST Wed Oct 09 2024

Since the previous advisory, a small eye feature has started 
appearing on geostationary infrared imagery with Leslie, surrounded 
by a ring of very cold (below -70 C) cloud top temperatures. This 
structure is also supported by an earlier SAR-RCM2 pass that showed 
a tight inner core with a radius of maximum wind that had contracted 
from yesterday. 00 UTC subjective Dvorak estimates from TAFB and SAB 
were T5.0/90-kt and T5.5/102-kt, respectively. Objective intensity 
estimates were somewhat lower, between 79-86 kt, and blending the 
data results in a 90 kt intensity this cycle. A Saildrone (SD-1036) 
appears to be near the path of Leslie, and is currently reporting 
sustained tropical-storm-force winds that are quickly increasing 
about 50 n mi northwest of the center. 

As noted previously, another saildrone (SD-1040) indicated that 
sea-surface temperatures near Leslie are warmer than expected, near 
29 C. At the same time, the hurricane is in a very narrow region of 
low vertical wind shear that should persist for another 6-12 h. 
While the interpolated intensity guidance is a bit lower, the raw 
model output of all four of the hurricane-regional models (HAFS-A/B, 
HMON, HWRF) show Leslie briefly becoming a major hurricane in 12 h. 
Because the raw model output from these intensity aids has been 
outperforming the interpolated guidance over the past day, the NHC 
intensity forecast will now show a 100 kt peak tomorrow morning. 
However, this peak is likely to be short-lived, as strong 
upper-level northerly flow, via outflow from Milton and Invest 93L, 
will soon overtake the hurricane, likely leading to rapid weakening. 
Those same hurricane-regional models show Leslie weakening below 
hurricane intensity in 36 h, and that rapid weakening continues to 
be reflected in the latest intensity forecast. While sheared puffs 
of deep convection may continue for a subsequent day or two, 
eventually Leslie is likely to lose the necessary convective 
organization to be classified as a tropical cyclone. The NHC 
forecast continues to show Leslie becoming post-tropical by the end 
of the weekend, though this could occur sooner than forecast given 
the proximity of very dry environmental air and high shear affecting 
the system.

Leslie continues to move northwestward, estimated at 315/7 kt this
evening. The track forecast is more straightforward, with Leslie
rounding the western edge of a subtropical ridge to its east,
resulting in a gradual turn northward and then northeastward over
the forecast period. With that said, there has been a notable
westward and poleward shift in the guidance this cycle, and the NHC
track forecast was moved in that direction, but not as far as the
latest TVCN and HCCA consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT  10/0300Z 22.6N  49.3W   90 KT 105 MPH
12H  10/1200Z 23.3N  49.9W  100 KT 115 MPH
24H  11/0000Z 24.4N  50.4W   80 KT  90 MPH
36H  11/1200Z 26.0N  50.1W   55 KT  65 MPH
48H  12/0000Z 28.4N  48.4W   45 KT  50 MPH
60H  12/1200Z 30.7N  45.5W   45 KT  50 MPH
72H  13/0000Z 33.0N  41.6W   45 KT  50 MPH
96H  14/0000Z 36.0N  31.0W   40 KT  45 MPH...POST-TROPICAL
120H  15/0000Z 37.1N  21.9W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin