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Hurricane Nigel Discussion Number  23
NWS National Hurricane Center Miami FL       AL152023
1100 PM AST Wed Sep 20 2023
 
Geostationary satellite imagery shows Nigel's outflow being
impinged upon by an upstream trough.  Still, the hurricane has
maintained its large, ragged eye surrounded by deep convection
with cloud top temperatures ranging from -60 to -70 degrees C.
Subjective Dvorak estimates from TAFB and SAB were both T4.5/77 kt,
and the initial intensity is held at 80 kt for this advisory.
 
The hurricane has begun to accelerate northeastward at an estimated
045/22 kt.  Nigel's forward speed is expected to increase through
Friday in the flow ahead of the mid-latitude trough exiting the
northeast US coast.  By the weekend, global models show Nigel
interacting with a large extratropical system over the North
Atlantic.  Little changes have been made to the latest NHC forecast,
which is largely an update of the previous prediction.
 
Nigel is nearing the 26 degree isotherm and should cross over it
in a few hours.  Deep-layer vertical wind shear is also expected to
increase significantly over the next 24 hours.  Nigel should begin
to transition into an extratropical cyclone soon, and this process
is expected to be complete in about 48 hours.  The official
intensity prediction shows gradual weakening through day 2, and
Nigel is forecast to become a powerful extratropical cyclone on
Friday.  By the end of the forecast period, Nigel should be absorbed
by the larger mid-latitude cyclone mentioned previously.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  21/0300Z 39.0N  50.4W   80 KT  90 MPH
 12H  21/1200Z 41.2N  46.4W   75 KT  85 MPH
 24H  22/0000Z 44.2N  39.1W   70 KT  80 MPH
 36H  22/1200Z 47.3N  31.2W   60 KT  70 MPH
 48H  23/0000Z 50.9N  25.4W   50 KT  60 MPH...POST-TROP/EXTRATROP
 60H  23/1200Z 54.9N  22.8W   50 KT  60 MPH...POST-TROP/EXTRATROP
 72H  24/0000Z 56.6N  22.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  25/0000Z 58.0N  23.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  26/0000Z...DISSIPATED
 
$$
Forecaster Bucci
 
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