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Hurricane Franklin Discussion Number  45
NWS National Hurricane Center Miami FL       AL082023
500 PM AST Thu Aug 31 2023
 
The cloud pattern of Franklin has continued to erode this afternoon.
Deep convection is limited to the southeastern portion of its
circulation, as strong shear continues to negatively affect the
system. Scatterometer data from today show the hurricane is still
producing a very large area of winds greater than 50 kt, though the
resolution limitations of the instrument do not allow for a peak
intensity estimate. The conventional satellite intensity estimates
continue to decrease, and the initial intensity is lowered to 80 kt
based on a blend of the latest objective and subjective estimates.
 
Franklin is expected to lose tropical characteristics over the next
day or so, with strong shear continuing over the system and
intrusions of drier mid-level air into the circulation as it
accelerates deeper into the mid-latitudes. However, this will not
immediately lead to significant weakening of the system. The GFS and
ECMWF both show an enhancement of hurricane-force winds on the
western side of the storm while the system interacts with a
baroclinic system and begins extratropical transition. Thus, the
near-term intensity forecast shows little change in strength, and
Franklin appears likely to maintain hurricane-force winds through
its extratropical transition in 36 h. Thereafter, a faster weakening
trend is shown through the rest of the forecast period, which is
consistent with the latest multi-model consensus aids.
 
The initial motion of Franklin is east-northeastward at 65/12 kt. A
northeastward acceleration is forecast during the next couple of
days while the cyclone moves within the flow between a subtropical
ridge over the central Atlantic and a deep-layer trough over
Atlantic Canada. From there, the track guidance generally supports a
continued northeastward motion over the northern Atlantic, and this
forecast shows a slightly faster motion beyond day 3 to reflect the
model consensus trends this cycle.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/2100Z 36.0N  60.1W   80 KT  90 MPH
 12H  01/0600Z 37.1N  57.7W   75 KT  85 MPH
 24H  01/1800Z 38.9N  53.8W   75 KT  85 MPH
 36H  02/0600Z 40.9N  49.7W   70 KT  80 MPH...POST-TROP/EXTRATROP
 48H  02/1800Z 43.2N  45.3W   60 KT  70 MPH...POST-TROP/EXTRATROP
 60H  03/0600Z 45.1N  41.3W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  03/1800Z 46.6N  37.6W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  04/1800Z 49.5N  31.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  05/1800Z 52.5N  27.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Reinhart
 
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