Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
705 AM EST Thu Feb 05 2015

Valid 00Z Fri Feb 06 2015 - 00Z Fri Feb 13 2015

Latest model guidance agrees upon a fairly active pattern with
multiple frontal passages that will bring variable weather and
occasionally breezy conditions.  The first front is currently
crossing the islands and accompanied by a few bands of showers. 
The next front should be drier and cross the islands around
Saturday. 

Then a deep central Pacific system and amplified trough aloft will
push a stronger and wetter front into the region early next week. 
As the front tracks into the northwestern islands precipitable
water values are forecast to be 1-1.5 inches or so... with the 00z
ECMWF in the lower half of that range and 00z/06z GFS runs on the
high end.  A notable uncertainty especially for the Big Island
will be the ultimate northward extent of a leading band of deep
moisture that may be drawn up from lower latitudes.  The past
couple ECMWF runs favor bringing this southeastern band of
moisture farther northward to the islands relative to GFS runs. 
GFS runs show a greater southeastward amplitude to the trough
aloft versus most other guidance from Mon onward and the 06z GFS
shows a modest trend in the ECMWF direction, so current evidence
seems to favor leaning 2/3 in the ECMWF direction for this part of
the forecast.  Behind the front expect a drying trend into Wed but
with some increase of deep moisture arriving from the west by Thu.

Rausch