Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
713 AM EST Mon Nov 16 2015

Valid 00Z Tue Nov 17 2015 - 00Z Tue Nov 24 2015

Guidance still shows an evolution toward a wetter pattern by the
latter half of the week and continuing into early next week. 
Troughing aloft to the northwest of the state will bring a front
toward but not reaching the northwestern islands as energy lingers
within the trough aloft.  An area of enhanced moisture, with some
precipitable water values reaching at least two inches, will move
into/across the state from the southeast Wed onward.  GFS runs
continue to show faster timing of this moisture than ECMWF runs
though forecast PWATs have become more similar.  A surface trough
may accompany this moisture surge as well.  Most guidance expects
the upper trough to the northwest of the state to broaden
gradually by Sat-Mon.  This trend with the trough may begin to
push the surface front/trough close to or into the islands and
help to focus a feed of moisture from the lower latitude tropics
in that time frame. 

Expect relatively light and primarily terrain-focused showers
early this week with PWATs generally in the 1-1.25 inch range. 
The Big Island should be first to see some enhancement in rainfall
with the moisture surge Wed-Thu.  By Fri or Sat into Mon the
consensus evolution at the surface and aloft would support more of
a north-south band of perhaps even heavier rainfall over the
western islands and drifting back east into the central islands.

Rausch