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Hurricane Darby Discussion Number 17
NWS National Hurricane Center Miami FL EP052022
500 AM HST Wed Jul 13 2022
Surprise! The eye of Darby reappeared this morning in IR imagery
after a hiatus overnight. Recent TAFB and SAB Dvorak estimates, and
the U-W CIMSS ADT all support an intensity of 90 kt, so Darby's
intensity was adjusted to that value. It should be stressed that
this appears to be a short-term fluctuation and has not changed the
overall thinking behind the intensity forecast, which calls for
Darby to generally weaken over the next few days.
Darby could maintain its intensity with small fluctuations today,
but all available intensity guidance indicates it will resume
weakening by tonight or tomorrow (if not sooner). This is likely
because it is moving through a marginal environment that includes
SSTs dropping below 26 deg C and 700-500 mb relative humidities
between 55-60 percent based on GFS and ECMWF-based SHIPS
diagnostics. After 24 h, an increase in wind shear should cause
Darby to weaken at a faster rate, particularly given the small size
of the hurricane. Simulated satellite output from the GFS, ECMWF and
HWRF models indicate Darby will lose all deep convection and become
post-tropical in about 60 h. The cyclone should subsequently
dissipate about a day after that. The NHC intensity forecast is
similar to the previous forecast and is near or just below the
intensity consensus (IVCN) at all forecast hours.
Virtually no change was made to the NHC track forecast. Darby
appears to have started an expected brief west-northwestward jog,
with an initial motion just north of due west at 14 kt. Darby should
complete that turn and move west-northwestward today, and then turn
westward tomorrow as it weakens through the end of the week. The
official track forecast is based heavily on the multi-model
consensus aids HCCA and TVCE.
FORECAST POSITIONS AND MAX WINDS
INIT 13/1500Z 15.0N 135.4W 90 KT 105 MPH
12H 14/0000Z 15.4N 137.4W 85 KT 100 MPH
24H 14/1200Z 16.0N 140.0W 75 KT 85 MPH
36H 15/0000Z 16.4N 142.5W 60 KT 70 MPH
48H 15/1200Z 16.6N 145.2W 50 KT 60 MPH
60H 16/0000Z 16.6N 148.0W 40 KT 45 MPH...POST-TROPICAL
72H 16/1200Z 16.3N 151.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 17/1200Z...DISSIPATED
$$
Forecaster D. Zelinsky
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