Central Pacific Basin Tropical Cyclones

Tropical Storm Darby Forecast Discussion

WTPA41 PHFO 161437

Tropical Storm Darby Discussion Number  29
NWS Central Pacific Hurricane Center Honolulu HI   EP052022
500 AM HST Sat Jul 16 2022

Deep convection associated with Darby remains limited, with only
a recent burst of convection north of the low-level circulation 
center over the past few hours. CIMSS SATCON intensity estimates 
remain around 40 kt. The current satellite intensity estimate 
from PHFO is 35 kt. Based on these data, and convective trends, the 
initial intensity remains at 40 kt.

The initial motion is now 270/19 kt. Low- to mid-level easterly 
flow associated with high pressure to the north supports the 
westerly track persisting until the system dissipates. The new 
forecast track is in the center of the tightly-clustered track 
guidance, with only a slight increase in forward speed compared to 
the previous forecast.

Darby will continue to weaken as it moves over 25-26C sea surface
temperatures and ingests drier air. This combined with moderate
shear will translate to the system becoming a post-tropical cyclone
by 24 hours, and the global models are in good agreement that the
system will dissipate to a surface trough by 36 hours. The new
intensity forecast is very similar to the previous forecast.


INIT  16/1500Z 17.5N 153.3W   40 KT  45 MPH
 12H  17/0000Z 17.3N 156.4W   35 KT  40 MPH
 24H  17/1200Z 17.2N 160.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 36H  18/0000Z...DISSIPATED

Forecaster Jelsema/Gibbs

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