[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 310251
TCDAT3

Hurricane Franklin Discussion Number  42
NWS National Hurricane Center Miami FL       AL082023
1100 PM AST Wed Aug 30 2023

Satellite imagery indicates the eye of Franklin is beginning to lose
its definition and become cloud-filled.  Radar imagery from Bermuda
shows outer rain bands have been crossing the island this evening,
bringing sustained tropical-storm-force winds and gusty conditions.
The initial intensity estimate for this advisory has been lowered to
85 kt based on a blend of the CI and Final T-numbers from both TAFB
and SAB.

Franklin has turned to the east-northeast at an estimated 12 kt,
passing to the north of Bermuda.  The hurricane is moving in the
flow between a subtropical ridge over the central Atlantic and a
trough over the northeastern U.S.  Track guidance in the first 48 h
remains decently-clustered, showing Franklin continuing generally
east-northeastward with an increased forward speed.  By 60 hours
and beyond, there is a larger spread in the guidance as Franklin
turns northeastward while it interacts with the upper-level trough.
The NHC track forecast is similar to the previous prediction and
lies between the simple consensus aid, TVCN, and the corrected
consensus aid, HCCA.

Based on the latest satellite trends, Franklin is continuing to
weaken in an environment of significant northerly vertical wind
shear.  Only minor adjustments have been made to the latest official
forecast, which shows gradual weakening through 60 hours as the
vertical wind shear is expected to increase.  By day 3, Franklin is
expected to become a strong extratropical cyclone, though this could
occur even sooner.


KEY MESSAGES:

1. Tropical storm conditions, mainly in gusts, are occuring on
Bermuda this evening while Franklin passes north of the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next day or two.


FORECAST POSITIONS AND MAX WINDS

INIT  31/0300Z 34.6N  64.5W   85 KT 100 MPH
 12H  31/1200Z 35.3N  62.3W   80 KT  90 MPH
 24H  01/0000Z 36.5N  59.0W   75 KT  85 MPH
 36H  01/1200Z 37.7N  55.8W   70 KT  80 MPH
 48H  02/0000Z 39.2N  52.3W   65 KT  75 MPH
 60H  02/1200Z 41.0N  49.1W   60 KT  70 MPH
 72H  03/0000Z 42.7N  46.3W   60 KT  70 MPH...POST-TROP/EXTRATROP
 96H  04/0000Z 45.9N  41.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  05/0000Z 50.1N  35.5W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci
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