Hurricane Kirk Discussion Number  21
NWS National Hurricane Center Miami FL       AL122024
1100 AM AST Fri Oct 04 2024

The satellite appearance of Kirk is a little less impressive than 
it was six hours ago, as the eye has become somewhat cloud-filled 
and the convective cloud tops have warmed a little.  Recent 
microwave imagery suggests that the hurricane may be starting an 
eyewall replacement cycle, with an outer convective band wrapped 
about three-quarters of the way around the eyewall.  The various 
objective and subjective satellite intensity estimates have trended 
downward, and based on a combination of these estimates the initial 
intensity is reduced to 120 kt.  The wind radii have been tweaked 
based on a recent ASCAT overpass.

The initial motion is 315/10.  Kirk is currently approaching a large 
break in the subtropical ridge caused by a deep-layer low centered 
near 33N 60W.  During the next 48-60 h, the hurricane should recurve 
through this break and accelerate northeastward into the 
mid-latitude westerlies.   After that time, the cyclone should move 
quickly east-northeastward across the northern and northeastern 
Atlantic.  There has been little change in the track guidance since 
the previous advisory, and the new forecast track has only minor 
adjustments from the previous track.

Fluctuations in intensity are likely during the next 24 h due to the 
expected eyewall replacement cycle.  After that, Kirk should 
encounter increasing southwesterly shear and move over cooler sea 
surface temperatures, which should cause a steady weakening.  
Extratropical transition is likely to begin between 60-72 h and be 
complete by 96 h, with Kirk becoming a strong extratropical cyclone 
over the northeastern Atlantic.  The new intensity forecast follows 
the general trends of the intensity guidance, and is closest to the 
GFS model during the extratropical stage.

Even though Kirk is expected to recurve over the open Atlantic, its
strong intensity and increasing size will result in large ocean
swells that will propagate far away from the hurricane. These swells
will likely increase the risk of dangerous surf and rip currents
across the Leeward Islands beginning later today, Bermuda and the
Greater Antilles by Saturday, much of the U.S. East Coast, Atlantic
Canada, and the Bahamas by Sunday, and the Azores by Monday. For
more information on this hazard, see products issued by your local
weather office.


FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 23.0N  48.9W  120 KT 140 MPH
12H  05/0000Z 24.4N  49.8W  115 KT 130 MPH
24H  05/1200Z 27.0N  50.3W  115 KT 130 MPH
36H  06/0000Z 30.3N  49.8W  110 KT 125 MPH
48H  06/1200Z 33.8N  48.3W   95 KT 110 MPH
60H  07/0000Z 37.6N  44.6W   85 KT 100 MPH
72H  07/1200Z 40.9N  39.3W   75 KT  85 MPH
96H  08/1200Z 45.3N  25.4W   55 KT  65 MPH...POST-TROP/EXTRATROP
120H  09/1200Z 48.0N   9.0W   50 KT  60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Beven