####018001972####
WTNT45 KNHC 211436

TCDAT5

 

Hurricane Nigel Discussion Number  25

NWS National Hurricane Center Miami FL       AL152023

1100 AM AST Thu Sep 21 2023



Nigel is still maintaining some deep convection, with cloud tops 

in bands to near -70 deg C.  However, increasing southwesterly 

vertical wind shear is beginning to cause an elongation of the cloud 

pattern toward the northeast.  Subjective Dvorak satellite 

classifications from TAFB and SAB continue to give Current 

Intensity numbers corresponding to 77 kt, and objective ADT 

estimates from UW-CIMSS are a little lower than that value.  The 

advisory intensity is held at 75 kt.



The current motion is quickly northeastward, or about 050/26 kt.  

Nigel is embedded in the flow on the southeastern side of a strong 

deep-layer mid-latitude trough.  This steering pattern should 

continue to carry the cyclone rapidly toward the northeast through 

tonight.  On Friday, Nigel should rotate around the eastern side of 

a large extratropical cyclone over the North Atlantic.



Vertical wind shear over Nigel should become very high within the 

next 24 hours, and the cyclone will be moving over significantly 

cooler waters later today.  Therefore weakening should occur, and 

global model guidance indicates that the system will become 

embedded in a frontal zone by early Friday.  In 2 to 3 days, Nigel 

is expected to merge with the large cyclone over the North 

Atlantic, and dissipate.

 

 

FORECAST POSITIONS AND MAX WINDS

 

INIT  21/1500Z 42.2N  45.0W   75 KT  85 MPH

 12H  22/0000Z 44.2N  38.8W   65 KT  75 MPH

 24H  22/1200Z 47.3N  30.8W   55 KT  65 MPH...POST-TROP/EXTRATROP

 36H  23/0000Z 51.0N  24.6W   50 KT  60 MPH...POST-TROP/EXTRATROP

 48H  23/1200Z 55.2N  22.9W   50 KT  60 MPH...POST-TROP/EXTRATROP

 60H  24/0000Z 57.4N  24.4W   45 KT  50 MPH...POST-TROP/EXTRATROP

 72H  24/1200Z...DISSIPATED

 

$$

Forecaster Pasch