Tropical Storm Rina Discussion Number   1
NWS National Hurricane Center Miami FL       AL182023
1100 AM AST Thu Sep 28 2023

Visible imagery early this morning indicates that a well-defined 
center has emerged to the northwest of persistent deep convective 
activity. A recent ASCAT pass and subjective Dvorak estimates from 
TAFB both indicate that the system has become a tropical cyclone. 
Thus, advisories have been initiated on Tropical Storm Rina. 

The recent partial ASCAT pass indicated winds in the 30-35 kt 
range but did not capture the most intense convection east of the 
center. Therefore, the current intensity for this advisory is set 
at 35 kt. Moderate deep-layer westerly shear is likely to limit 
intensification in the short term, and this shear is expected to 
increase this weekend and early next week. Persistent shear, in 
addition to the close proximity and uncertain interaction with 
Tropical Storm Philippe, should limit intensification during the 
forecast period. The NHC forecast is in the middle of the guidance 
envelope and very close to the HCCA solution. Rina is expected to 
remain a tropical storm throughout the forecast period, though some 
of the regional hurricane models do indicate a faster rate of 
intensification during the next several days compared to the NHC 
forecast. 

Rina is moving north-northwestward, with an initial forward speed 
near 9 kt. The tropical storm should begin to turn more westward 
today and continue this general motion for the next several days. 
Early next week, the system is expected to turn northward as a 
mid-level ridge builds to the west. The NHC forecast is a blend of 
the HCCA and TVCN consensus guidance throughout the forecast 
period. Confidence in the track forecast is lower than normal based 
on the model spread and uncertainty regarding the potential 
interaction with Tropical Storm Philippe during the next several 
days.

FORECAST POSITIONS AND MAX WINDS

INIT  28/1500Z 17.4N  45.0W   35 KT  40 MPH
12H  29/0000Z 18.5N  45.8W   35 KT  40 MPH
24H  29/1200Z 19.2N  46.8W   40 KT  45 MPH
36H  30/0000Z 19.6N  47.8W   45 KT  50 MPH
48H  30/1200Z 19.9N  49.0W   50 KT  60 MPH
60H  01/0000Z 20.4N  50.4W   50 KT  60 MPH
72H  01/1200Z 21.1N  52.2W   45 KT  50 MPH
96H  02/1200Z 23.9N  56.2W   40 KT  45 MPH
120H  03/1200Z 26.2N  58.2W   40 KT  45 MPH

$$
Forecaster Hogsett/Cangialosi