Eastern Pacific Basin Tropical Cyclones

Hurricane Darby Forecast Discussion

WTPZ45 KNHC 120233

Hurricane Darby Discussion Number  11
NWS National Hurricane Center Miami FL       EP052022
500 PM HST Mon Jul 11 2022

Darby has been generally steady in strength during the past several 
hours and remains a category 4 hurricane on the Saffir-Simpson 
Hurricane Wind Scale. It maintains a classic major hurricane 
structure with well-defined outflow in all quadrants, a symmetric 
cloud pattern, and a distinct small eye (less than 10 n mi in 
diameter). Satellite images indicate that the eye has become even 
more defined over the past few hours, but deep convection has been 
weakening a little to the west of the eye. All of the satellite 
intensity estimates have plateaued and suggest that Darby still has 
peak winds of around 120 kt. Although the hurricane is very 
powerful, it is quite compact with tropical-storm-force winds 
estimated to only extend 50 n mi from the center.

The hurricane has been moving westward, or 275 degrees, at 15 kt. A
general west to west-northwest motion at a slightly slower pace is
expected during the next few days as Darby continues to move on the
south or southwest side of a mid-level ridge, taking the system into
the central Pacific basin in 60-72 hours. After that time, the
weakening system is expected to be steered due westward by the
low-level flow. There are some speed differences in the models, but
they generally show the same theme. This forecast lies near the
middle of the guidance envelope, and roughly between the GFS and
ECMWF models.

Darby is likely near its peak intensity. The major hurricane will
be moving over progressively cooler waters and crossing the 26
degree C isotherm in about 24 hours. In addition, Darby will be
moving into a drier airmass, which should accelerate the weakening
trend. In a few days when Darby is over the central Pacific, a mid-
to upper-level trough should induce strong westerly shear and cause
Darby to become a post-tropical cyclone in about 4 days. The NHC
intensity forecast is similar to the previous one and fairly close
to the IVCN and HCCA consensus models.


INIT  12/0300Z 14.9N 126.6W  120 KT 140 MPH
 12H  12/1200Z 15.0N 128.7W  120 KT 140 MPH
 24H  13/0000Z 15.1N 131.3W  115 KT 130 MPH
 36H  13/1200Z 15.5N 133.9W  100 KT 115 MPH
 48H  14/0000Z 16.1N 136.4W   80 KT  90 MPH
 60H  14/1200Z 16.7N 139.0W   65 KT  75 MPH
 72H  15/0000Z 17.3N 141.6W   50 KT  60 MPH
 96H  16/0000Z 17.6N 147.1W   35 KT  40 MPH...POST-TROPICAL
120H  17/0000Z 17.4N 153.5W   30 KT  35 MPH...POST-TROP/REMNT LOW

Forecaster Cangialosi

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