Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
751 AM EDT Tue Aug 23 2016

Valid 00Z Wed Aug 24 2016 - 00Z Wed Aug 31 2016

Models and ensembles continue to show a low-mid level ridge
building in from the northeast over the rest of the week and
persisting through weekend into early next week.

ECMWF/GFS show the axis of high precipitable water values
extending across the islands through Wed with peak values today
near  inches on the big island.
The combination of available deep moisture, a modest weakness
aloft through Tuesday, as well as sea breeze boundaries allowed by
relatively weak trade flow, lead to possible locally heavy
downpours today and tomorrow.

The ECMWF/GFS forecasts trend sharply drier on Thu., so the threat
of heavy showers gets reduced as a result. From Thursday onward
through the weekend expect a drier pattern with greater windward
focus for showers that occur. 

The models/ensemble means have good agreement in the large scale
pattern through the weekend, supporting a consensus based forecast
approach.  Tropical systems east of the islands early next week
will need to be monitored for potential impacts later in the week.

Petersen