Hurricane Kristy Forecast Discussion

000
WTPZ42 KNHC 231442
TCDEP2

Hurricane Kristy Discussion Number   8
NWS National Hurricane Center Miami FL       EP122024
800 AM MST Wed Oct 23 2024

The impressive rapid intensification of Kristy has continued this 
morning. The gradually warming eye of the hurricane is surrounded by 
a ring of very deep convection, with infrared cloud tops as cold as 
-75 to -80 deg C. GOES-West derived motion winds indicate good 
upper-level outflow, particularly over the southern and western 
portions of the circulation. Subjective Dvorak classifications were 
a consensus T5.5/102-kt from TAFB and SAB at 12 UTC. Satellite 
trends suggest Kristy has kept strengthening since that time, and 
the initial intensity is set at 110 kt, following the rising 
objective estimates from UW-CIMSS.

The hurricane is moving quickly westward (265/17 kt) while being 
steered by a strong subtropical ridge to its north. This quick 
westward motion should continue for the next 24-36 h. Then, an 
upper-level trough between the Hawaiian Islands and the west coast 
of the United States is forecast to erode the western extent of the 
ridge. As a result, Kristy is expected to move toward the 
west-northwest and northwest late this week and into the weekend. A 
westward motion is shown by day 5, as it is anticipated that Kristy 
will become highly sheared and decoupled, with the vertically 
shallow vortex steered by the low-level ridge. No significant 
changes were made to the latest NHC track forecast.

Kristy is a relatively small hurricane that remains susceptible to 
rapid intensity fluctuations in a weak shear environment over warm 
SSTs. The latest GFS and ECMWF SHIPS output shows a 50 to 60 percent 
chance of a 20-kt increase during the next 12 h, and the satellite 
trends suggest continued near-term strengthening is likely. The 
updated NHC forecast reflects these signals and lies above the 
intensity guidance in the near term, showing Kristy peaking as a 
category 4 hurricane on Thursday. By Friday, the aforementioned 
trough is expected to impart increased shear on the hurricane, which 
should induce weakening through the rest of the 5-day forecast 
period. With SHIPS-diagnosed shear values of 40-50 kt by the 
weekend, Kristy is forecast to quickly weaken over the weekend and 
degenerate to a post-tropical remnant low by 120 h.   


FORECAST POSITIONS AND MAX WINDS

INIT  23/1500Z 14.3N 113.9W  110 KT 125 MPH
 12H  24/0000Z 14.2N 116.4W  125 KT 145 MPH
 24H  24/1200Z 14.1N 119.7W  130 KT 150 MPH
 36H  25/0000Z 14.3N 122.5W  125 KT 145 MPH
 48H  25/1200Z 15.1N 125.1W  115 KT 130 MPH
 60H  26/0000Z 16.5N 127.3W  105 KT 120 MPH
 72H  26/1200Z 18.0N 129.3W   90 KT 105 MPH
 96H  27/1200Z 20.5N 132.5W   55 KT  65 MPH
120H  28/1200Z 21.0N 136.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Reinhart