Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
811 AM EDT Tue Apr 04 2017

Valid 00Z Wed Apr 05 2017 - 00Z Wed Apr 12 2017

Moderate to brisk trades as supported by an east-west surface
ridge north of the state should briefly weaken over the next
couple days with the passage of a front that will remain north of
the islands.  Trailing high pressure passing by to the north
around Friday-Friday night will likely strengthen trades again for
the late week time frame.  Guidance is consistent in suggesting
that winds will turn southeasterly during the weekend into the
start of next week as the high continues into the eastern Pacific
and a cold front approaches from the northwest.  This front should
reach the northwestern islands by next Tuesday.  There is modest
spread for frontal position at that time with mixed comparisons
making it difficult to have confidence in a particular solution. 
The 00z GFS/ECMWF are fairly similar with frontal position versus
the slower 06z GFS but the 00z GFS is a little faster than other
models/means for the supporting shortwave energy aloft.  The
CMC/CMC mean are stronger with the ridge aloft that passes over
the state late in the week and thus slower with the upstream
energy/surface front.  Expect below normal precipitable water
values and relatively high heights aloft through late week into
the weekend to favor only light showers over windward terrain for
most of the period.  The front approaching early next week may
provide at least a modestly increased focus for rainfall.

Rausch