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Tropical Storm Kenneth Discussion Number   7
NWS National Hurricane Center Miami FL       EP132023
800 PM PDT Wed Sep 20 2023
 
It appears that southerly mid-level shear has set in over Kenneth 
during the day, and the surface center is now located on the 
southern side of the ongoing convective mass.  Dvorak final-T 
numbers are a consensus 3.0 from TAFB and SAB, so the initial 
intensity remains 45 kt.

The shear appears to have pulled Kenneth's center farther to the 
north, and as a result, the storm has turned northwestward with an 
initial motion of 310/10 kt.  A turn toward the north-northwest and 
north is expected over the next 36 hours as Kenneth moves around 
the western periphery of the subtropical ridge.  Partly because of 
the required adjustment of the initial position, the track guidance 
has shifted significantly to the north and east on this cycle.  The 
new NHC track forecast lies very close to the GFS, ECMWF, TVCE, and 
HCCA aids, particularly during the first 36 hours of the forecast, 
and is as much as 30-40 n mi to the right of the previous 
prediction.

As is often the case, the mid-level shear affecting the cyclone was 
not foreseen, as nearly all shear diagnostics show that the shear in 
a deeper layer of the atmosphere is currently very low.  That said, 
even the deep-layer shear is forecast to increase to 
moderate-to-strong levels in the next 12-24 hours.  Simultaneously, 
Kenneth will be moving over increasingly cooler waters that are less 
than 26 degrees Celsius.  Therefore, weakening is expected to begin 
by 24 hours, and strong shear and a drier, more stable atmosphere 
should cause Kenneth to degenerate into a remnant low by late 
Friday.  The remnant low could hang around for a few days, opening 
up into a trough by Sunday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 16.9N 125.2W   45 KT  50 MPH
 12H  21/1200Z 17.6N 126.0W   45 KT  50 MPH
 24H  22/0000Z 19.0N 126.8W   40 KT  45 MPH
 36H  22/1200Z 20.7N 126.9W   35 KT  40 MPH
 48H  23/0000Z 22.1N 126.8W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  23/1200Z 23.1N 126.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  24/0000Z 23.8N 127.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  25/0000Z...DISSIPATED
 
$$
Forecaster Berg
 
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