[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 030842
TCDAT1

Tropical Storm Earl Discussion Number   2
NWS National Hurricane Center Miami FL       AL062022
500 AM AST Sat Sep 03 2022

Satellite imagery and radar data from Guadeloupe show that Earl
remains a sheared tropical cyclone, with the low-level center
located to the west of the main convective mass. Various satellite
intensity estimates are in the 25-45 kt range and have changed
little since the last advisory.  Based on this, the initial
intensity remains 35 kt.  A NOAA Hurricane Hunter aircraft will
investigate Earl starting near 1000 UTC.

The initial motion is 285/11.  The track guidance remains in good
agreement that Earl should move west-northwestward and
northwestward with a decrease in forward speed for the next couple
of days as it is steered by the subtropical ridge. There is little
change in this part of the forecast track from the previous
advisory.  After that time, a slower motion toward the north and
eventually north-northeast is expected as a mid- to upper-level
trough develops over the Atlantic to the west and north of Earl.
The guidance envelope for the latter part of the forecast track has
shifted eastward, and while the new forecast track is also nudged
eastward it is west of the consensus models from 60-120 h.

Earl is feeling the effects of moderate westerly shear, and current
indications are this will continue for the next 48 h or so.  Thus,
the intensity forecast calls for modest strengthening during this
time.  The intensity forecast becomes more uncertain as Earl turns
northward.  While some shear is likely to continue, the dynamical
models are in good agreement that the cyclone will strengthen,
possibly due to a favorable interaction to the aforementioned
upper-level trough.  However, there is poor agreement between the
models in the details of this interaction.  Given that, the
intensity forecast from 72-120 h will show a little more
strengthening than the previous forecast.  However, the forecast
intensities are on the low side of the guidance envelope.

Tropical-storm-force winds are forecast to remain on the northern
and eastern side of the circulation, and as a result, are not
expected to move across the northern Leeward Islands, the Virgin
Islands, or Puerto Rico.  However, any southward shift of Earl's
center would increase the risk of tropical-storm-force winds in
those areas.


KEY MESSAGES:

1.  Tropical Storm Earl is forecast to pass near or just to the
north of the northern Leeward Islands, the Virgin Islands, and
Puerto Rico over the weekend.  Gusty winds, especially in squalls,
area possible on those islands over the next day or two.

2.  Heavy rainfall from Earl is expected to lead to limited flash,
urban, and small stream flooding impacts over the Leeward Islands,
U.S. and British Virgin Islands, and Puerto Rico this weekend.
Rapid rises on rivers are possible in Puerto Rico.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 18.7N  61.4W   35 KT  40 MPH
 12H  03/1800Z 19.2N  62.8W   35 KT  40 MPH
 24H  04/0600Z 19.9N  64.5W   40 KT  45 MPH
 36H  04/1800Z 20.6N  65.6W   40 KT  45 MPH
 48H  05/0600Z 21.2N  66.4W   40 KT  45 MPH
 60H  05/1800Z 21.8N  67.0W   45 KT  50 MPH
 72H  06/0600Z 22.6N  67.2W   45 KT  50 MPH
 96H  07/0600Z 24.0N  67.0W   50 KT  60 MPH
120H  08/0600Z 25.5N  65.5W   55 KT  65 MPH

$$
Forecaster Beven
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