WTPA43 PHFO 250241
TCDCP3

TROPICAL STORM DARBY DISCUSSION NUMBER  54
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP052016
500 PM HST SUN JUL 24 2016

Earlier thunderstorms southeast of Darby's centered dissipated
but vigorous thunderstorms just northeast of the center flared up
this afternoon with tops colder than -65C. The morning Hurricane
Hunter mission into Darby continued through mid-day with a maximum
surface wind of 37 kt found over the water east of the center.
Based on the aircraft recon data and the recent burst in deep
convection very close to Oahu and Kauai, Darby has been held at 35
kt for this advisory package. This could be generous, especially
considering that subjective Dvorak estimates all came in at 30 kt
and that no surface stations on Kauai and Oahu have reported
tropical storm force conditions thus far. Note that this was the
final mission into Darby. A big mahalo to the 53rd Weather
Reconnaissance Squadron for their outstanding support over the past
several days.
 
Darby is moving at 325/10 kt to the southwest of a lower and
middle-level pressure ridge. The main dynamical objective aids
remain tightly clustered and continue to indicate that Darby will
move northwestward over or near Kauai tonight, and continue toward
the northwest over the next 2 to 3 days while weakening to a
post-tropical remnant low. The forecast track for this package
remains close to the previous track and the dynamical consensus.
 
Current marginal sea surface temperatures will cool along the
forecast track and vertical shear, while forecast to be less
persistent than the previous cycle, should remain relatively strong
over the next day or so. As a result, the current forecast calls for
Darby to weaken to a tropical depression overnight, then become a
post-tropical remnant low in 48 hours. This is a faster weakening
than indicated by the intensity consensus. 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/0300Z 21.7N 158.9W   35 KT  40 MPH
 12H  25/1200Z 22.7N 160.0W   30 KT  35 MPH
 24H  26/0000Z 23.8N 161.5W   30 KT  35 MPH
 36H  26/1200Z 25.0N 163.2W   30 KT  35 MPH
 48H  27/0000Z 26.4N 164.7W   30 KT  35 MPH...POST-TROP/REMNT LOW
 72H  28/0000Z 29.9N 166.8W   25 KT  30 MPH...DISSIPATED
 
$$
Forecaster Kodama