Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
812 AM EDT Fri May 19 2017

Valid 00Z Sat May 20 2017 - 00Z Sat May 27 2017

From now into the weekend expect trades to be in the lighter half
of the spectrum, allowing for some diurnal sea breeze influence on
shower activity.  By Sunday-Monday a front will approach/stall
near the northern islands.  The front will dissipate with time but
leave behind a narrow axis of higher moisture.  Trailing high
pressure will strengthen trades in the early-mid week period. 
Then weakening of the high will promote a gradual slackening of
trades late in the week.  By next Thursday-Friday the 00z/06z GFS
runs differ from most other guidance with a western
Pacific/Aleutians system, shifting the central Pacific pattern
enough to give the state slightly stronger trades than the
majority cluster including the 00z ECMWF and 00z GEFS/ECMWF means.
 At this time would recommend the non-GFS cluster as the more
likely scenario toward late next week.  From Monday onward expect
more windward shower focus with the possibility for a little rain
to extend into other locales at times.

Rausch