[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 040236
TCDAT5

Hurricane Danielle Discussion Number  12
NWS National Hurricane Center Miami FL       AL052022
1100 PM AST Sat Sep 03 2022

Danielle has, once again, become a hurricane.  The satellite
presentation consists of a single, primary curved band wrapping
around approximately 95 percent of the surface circulation center.
The Dvorak satellite intensity estimates from TAFB and SAB are
a unanimous T-4.0, yielding 65 kt which is the initial intensity
for this advisory.

The environment appears conducive for gradual strengthening during
the short term.  Beyond the 48-hour period, however, decreasing
oceanic temperatures, an increasingly stable environment, and
increasing vertical wind shear should induce a slow weakening trend.
The latest Florida State Cyclone Phase Analysis, using the GFS,
shows Danielle commencing an extratropical transition on the 6th. In
that model, the cyclone maintains a moderate to deep warm core but
becomes highly asymmetric (frontal characteristics) in the lower
troposphere around the 8th.  The analysis and the SHIPS statistical
intensity model show Danielle completing its transition near the end
of the 5-day forecast period with a well-developed cold core above
600 mb.  The NHC forecast follows suit and shows Danielle as an
extratropical cyclone at 120 h.  The official intensity forecast now
shows a peak intensity of 80 kt in 36 hours and agrees with the NOAA
HCCA and IVCN intensity consensus aids.

Danielle has been drifting toward the west during the past several
hours and this general motion is expected to continue through
Sunday as the hurricane remains in weak steering currents to the
south of high pressure anchored over the North Atlantic.
Afterward, a turn to the north is forecast by Sunday night,
followed by an acceleration toward the northeast in response to a
deep-layer trough moving over the Canadian Maritimes and toward
Danielle.  The NHC forecast is an update of the previous one
through 72 hours, and is adjusted slightly south to lie closer to
the various consensus models.


FORECAST POSITIONS AND MAX WINDS

INIT  04/0300Z 38.1N  45.1W   65 KT  75 MPH
 12H  04/1200Z 38.2N  45.4W   70 KT  80 MPH
 24H  05/0000Z 38.7N  45.1W   75 KT  85 MPH
 36H  05/1200Z 39.5N  44.4W   80 KT  90 MPH
 48H  06/0000Z 40.4N  43.5W   80 KT  90 MPH
 60H  06/1200Z 41.4N  42.2W   75 KT  85 MPH
 72H  07/0000Z 42.4N  40.2W   70 KT  80 MPH
 96H  08/0000Z 44.5N  35.0W   65 KT  75 MPH
120H  09/0000Z 46.1N  28.4W   60 KT  70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Roberts
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