Tropical Storm Leslie Forecast Discussion

000
WTNT43 KNHC 120236
TCDAT3

Tropical Storm Leslie Discussion Number  39
NWS National Hurricane Center Miami FL       AL132024
1100 PM AST Fri Oct 11 2024

Convection associated with Leslie has been increasing during the 
past several hours as the cyclone moves into an area of temporarily 
decreased shear. A recent ASCAT overpass showed winds of 40-45 kt in 
the southeastern quadrant, and based on these data the initial 
intensity is held at 45 kt.  The scatterometer data also suggest 
that the circulation is becoming somewhat distorted due to the rapid 
northeastward motion.

The initial motion is now 035/19 kt.  The cyclone is accelerating 
northeastward as it moves into the mid-latitude southwesterly flow 
to the east of a deep-layer trough over the northwestern Atlantic.  
This general motion should continue for 24 h or so.  After that, 
Leslie or its remnants should turn eastward and east-southeastward 
on the southwestern side of another deep-layer trough located over 
the northeastern Atlantic, with this motion continuing until the 
system dissipates.  There are no significant changes in the track 
guidance since the previous advisory, and the new forecast track is 
similar to the previous track.

Shear over Leslie should remain relatively low for the next    12-18 
h, allowing the current convection to continue and the system to 
maintain tropical cyclone status during that time.  The global 
models have come into good agreement that Leslie will merge with a 
frontal system to become extratropical between 24-36 h, and thus the 
intensity forecast status has been adjusted accordingly.  The 
extratropical cyclone should subsequently weaken and be absorbed 
into the larger system over the eastern Atlantic by 96 h. It should 
be noted that while the models show a closed low pressure area 
through 72 h, the circulation could degenerate into an open trough 
before then due to the fast forward speed.


FORECAST POSITIONS AND MAX WINDS

INIT  12/0300Z 29.3N  47.9W   45 KT  50 MPH
 12H  12/1200Z 31.8N  45.0W   45 KT  50 MPH
 24H  13/0000Z 34.8N  39.5W   45 KT  50 MPH
 36H  13/1200Z 36.7N  33.6W   40 KT  45 MPH...POST-TROP/EXTRATROP
 48H  14/0000Z 37.1N  28.3W   35 KT  40 MPH...POST-TROP/EXTRATROP
 60H  14/1200Z 36.0N  23.5W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  15/0000Z 35.3N  19.2W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  16/0000Z...DISSIPATED

$$
Forecaster Beven