[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 090254
TCDAT1

Hurricane Earl Discussion Number  25
NWS National Hurricane Center Miami FL       AL062022
1100 PM AST Thu Sep 08 2022

The satellite and airborne radar presentation of Earl has continued
to degrade this evening.  The eye has expanded to 50 n mi wide,
become more ragged in appearance, and is open to the south.  A NOAA
Hurricane Hunter aircraft investigating the system has only found
peak flight-level winds of 89 kt and surface wind measurements of 75
kt.  The minimum central pressure has also risen to a reported 964
mb.  Based on these data and accounting for potential undersampling
of the wind field, the initial intensity has been lowered to 80 kt
on this advisory cycle.

The hurricane is moving north-northeastward at 13 kt.  The forward
motion is expected to increase as Earl is caught up in the
southwesterly flow between a mid-level ridge to the east, and a
digging mid-latitude trough to the northwest.  A mid-level trough
moving off the eastern seaboard is forecast to capture the storm and
slow Earl's motion off the Canadian coast.  There is some
uncertainty in timing of this interaction which is leading to a
larger spread in model track guidance in the 60-96 h forecast
range.

Statistical model guidance insists that Earl has another day or so
of conducive atmospheric and oceanic conditions in which to
strengthen.  However, the recent degradation in structural
organization of the hurricane may be difficult to overcome in a
short period of time.  The peak intensity of the official forecast
has been lowered to 100 kt at 24 hours.  Beyond a day, the vertical
wind shear is predicted to increase dramatically and induce rapid
weakening, and extratropical transition is likely to occur within 48
hours.


KEY MESSAGES:

1.  Although Earl's center is forecast to pass southeast of Bermuda,
tropical-storm-force winds are expected on the island tonight into
tomorrow morning.

2.  Swells generated by Earl are affecting Bermuda and are expected
to reach the U.S. East Coast tonight. These swells are likely to
cause life-threatening surf and rip current conditions through the
weekend.  Please consult products from your local weather office.


FORECAST POSITIONS AND MAX WINDS

INIT  09/0300Z 31.3N  63.7W   80 KT  90 MPH
 12H  09/1200Z 33.3N  61.8W   90 KT 105 MPH
 24H  10/0000Z 36.9N  57.9W  100 KT 115 MPH
 36H  10/1200Z 40.7N  53.9W   90 KT 105 MPH
 48H  11/0000Z 43.3N  51.3W   70 KT  80 MPH...POST-TROP/EXTRATROP
 60H  11/1200Z 44.2N  50.4W   55 KT  65 MPH...POST-TROP/EXTRATROP
 72H  12/0000Z 45.0N  49.2W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  13/0000Z 45.8N  46.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  14/0000Z 46.5N  41.2W   40 KT  45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci/Pasch
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