Tropical Storm Joyce Discussion Number   4
NWS National Hurricane Center Miami FL       AL112024
500 AM AST Sat Sep 28 2024

Satellite imagery this morning indicates that Joyce has changed 
little in organization since the last advisory, with the low-level 
center located on the southern edge of the convection due to 
southerly shear. Satellite intensity estimates are clustered near 
45 kt and have changed little during the past 6 h, and based on 
this the initial intensity remains 45 kt.

The initial motion is just a little to the right of the previous 
motion, 305/9 kt.  Joyce is on the south side of a narrow 
subtropical ridge, which is going to weaken and break as a 
deep-layer trough amplifies over the central Atlantic during the 
next few days.  This evolution should cause Joyce to move slowly to 
the west-northwest and northwest for a couple of days, followed by 
an even slower motion toward the north.  The track guidance is in 
generally good agreement through 48 h, but after that time there is 
some divergence due to a couple of the regional hurricane models 
forecasting a stronger Joyce to recurve into the aforementioned 
trough.  As with the previous advisory, the track forecast calls for 
a weaker Joyce to move slowly and not be fully picked up by the 
trough, and the new forecast track has no significant changes from 
the previous forecast.

Joyce is experiencing moderate southerly shear, and the global
models forecast this to continue for the next several days.  In 
addition, the storm will be moving into a gradually drier and 
subsident environment.  Thus, the new intensity forecast is similar 
to the previous forecast in calling for little change in strength 
during the next 12 hours, followed by gradual weakening. Simulated 
satellite imagery from the GFS and ECMWF models suggest that Joyce 
will lose its convection and become a remnant low by day 3, if not 
sooner.  The remnant low should degenerate into a trough by day 4 or 
5, with the remnants subsequently being absorbed by another system 
approaching from the east.


FORECAST POSITIONS AND MAX WINDS

INIT  28/0900Z 19.5N  45.3W   45 KT  50 MPH
12H  28/1800Z 20.0N  46.7W   45 KT  50 MPH
24H  29/0600Z 20.5N  48.2W   40 KT  45 MPH
36H  29/1800Z 21.1N  49.2W   40 KT  45 MPH
48H  30/0600Z 21.7N  49.6W   35 KT  40 MPH
60H  30/1800Z 22.3N  49.7W   30 KT  35 MPH
72H  01/0600Z 22.6N  49.7W   25 KT  30 MPH...POST-TROP/REMNT LOW
96H  02/0600Z 23.0N  50.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  03/0600Z...DISSIPATED

$$
Forecaster Beven