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Tropical Storm Rina Discussion Number   5
NWS National Hurricane Center Miami FL       AL182023
1100 AM AST Fri Sep 29 2023

Over the last few hours, Rina's center has become exposed with less 
convective organization noted in the GOES-E satellite imagery. The 
subjective satellite intensity estimates held steady at 45 kt, 
while the objective estimates are lower around 35 to 40 kt. Based 
on a blend of these data, the initial intensity is set to 40 kt. 

Rina's current motion remains nearly the same, moving 
north-northwestward at 335/5 kt. Most of the track guidance shows 
Rina moving generally northwestward through the weekend between 
nearby Tropical Storm Philippe and a subtropical ridge over the 
central Atlantic. By early next week, Rina will start to make a turn 
to the north within the flow between the subtropical ridge and an 
upper-level trough moving across the western Atlantic. Most of the 
model guidance shows a shift to the right of the previous forecast 
track with a faster forward speed. The official NHC forecast track 
reflects these trends and is adjusted closer to the latest consensus 
aids. The one notable outlier is the GFS, which shows more of an 
interaction between Rina and Philippe. 

The exposed center of Rina indicates a sheared environment, and 
strong deep-layer shear (partially associated with Philippe) is 
forecast to persist during the next few days. The official NHC track 
intensity is held steady through the next day or so, followed by 
gradual weakening as supported by the latest intensity guidance. By 
early next week, Rina is forecast to become a post-tropical remnant 
low as it begins that turn to the north and open up into a trough by 
day 5. Some model guidance suggests dissipation could occur even 
sooner. The NHC intensity forecast is based on this weakening 
trend, in agreement with the multi-model consensus. 

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/1500Z 19.4N  47.0W   40 KT  45 MPH
 12H  30/0000Z 19.8N  47.6W   40 KT  45 MPH
 24H  30/1200Z 20.4N  48.8W   40 KT  45 MPH
 36H  01/0000Z 21.5N  50.3W   35 KT  40 MPH
 48H  01/1200Z 22.7N  52.2W   35 KT  40 MPH
 60H  02/0000Z 24.0N  53.8W   30 KT  35 MPH
 72H  02/1200Z 25.6N  55.0W   30 KT  35 MPH
 96H  03/1200Z 29.0N  55.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  04/1200Z...DISSIPATED
 
$$
Forecaster A. Reinhart/B. Reinhart
 
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