Hurricane Franklin Discussion Number  44
NWS National Hurricane Center Miami FL       AL082023
1100 AM AST Thu Aug 31 2023

Satellite imagery indicates that Franklin continues to battle 
strong northerly shear associated with the outflow from Idalia. 
Recent microwave data confirm its inner core has eroded, with deep 
convection confined to the southeastern portion of the circulation. 
There is a large spread in the recent intensity estimates, with 
higher objective estimates than the consensus T4.5/5.0 Dvorak 
classifications from SAB and TAFB. Given this uncertainty, the 
initial intensity is held at 85 kt for this advisory. 

Some gradual weakening is forecast during the next couple of days 
while Franklin contends with the negative impacts of deep-layer 
shear. However, the cyclone is expected to remain at or near 
hurricane strength while increased baroclinic forcing and 
interaction with the upper trough support its extratropical 
transition. The GFS and ECMWF show fronts extending into Franklin's 
circulation by 48 h, likely signaling completion of this process. 
Therefore, the NHC forecast shows Franklin becoming a powerful 
extratropical cyclone in 48 h. Thereafter, further weakening is 
forecast while the cyclone moves deeper into the mid-latitudes, in 
agreement with the latest global guidance.

Franklin is moving east-northeastward (70/12 kt) within the flow 
between a deep-layer trough moving off the coast of the northeastern 
U.S. and eastern Canada and a subtropical ridge to the east. The 
latest track guidance remains in very good agreement that Franklin 
will accelerate toward the east-northeast or northeast during the 
next couple of days. The NHC track forecast in the near term is 
essentially an update of the previous one and remains close to the 
TVCN and HCCA aids. Track model solutions diverge beyond day 3 
regarding the track and speed of motion for the extratropical 
cyclone over the northern Atlantic, and in general the latest NHC 
forecast lies between the consensus aids and ensemble means. 


FORECAST POSITIONS AND MAX WINDS

INIT  31/1500Z 35.1N  61.6W   85 KT 100 MPH
12H  01/0000Z 36.3N  59.3W   75 KT  85 MPH
24H  01/1200Z 37.8N  55.8W   70 KT  80 MPH
36H  02/0000Z 39.7N  51.7W   70 KT  80 MPH
48H  02/1200Z 42.0N  47.2W   65 KT  75 MPH...POST-TROP/EXTRATROP
60H  03/0000Z 44.2N  43.1W   55 KT  65 MPH...POST-TROP/EXTRATROP
72H  03/1200Z 45.9N  39.1W   50 KT  60 MPH...POST-TROP/EXTRATROP
96H  04/1200Z 48.0N  33.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  05/1200Z 50.5N  28.0W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart