Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
820 AM EDT Sun Aug 09 2015

Valid 00Z Mon Aug 10 2015 - 00Z Mon Aug 17 2015

...Hurricane Hilda to affect the Hawaiian Islands this week in
weakened form...

...Locally heavy rain possible...


Surface high pressure near 40N/160W will continue to slide
eastward over the next couple of days, keeping trades in place
over Hawai'i through Tuesday. All interests then turn to current
Hurricane Hilda. Please consult the CPHC for the latest forecast
information. As of the 09Z advisory, the track of Hilda is to the
NW then WNW by late Thursday, about 70 miles from the Big Island.
Though weakened, the circulation should still usher in an increase
in moisture and increase the chance for heavy rain over much of
the island chain later this week into the weekend. The models
continue to shift their forecasts, with the consensus bringing the
circulation westward along or just south of 20N. A blend between
the ECMWF and GFS appears reasonable for a forecast scenario
Thu-Sat as the system passes through the area. Model/ensemble
cumulative QPF range between about 0.5" - 9.0" (not too helpful)
on the windward side and lower elevations of the islands with the
best clustering around 2-4". QPF in the mountains are much higher
(>18") per the 06Z GFS but much less per the ECMWF. Needless to
say, much uncertainty remains. Lingering moisture will likely keep
at least scattered showers in the forecast through next Sunday.


Fracasso