Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
713 AM EST Wed Nov 12 2014

Valid 00Z Thu Nov 13 2014 - 00Z Thu Nov 20 2014

An initial frontal boundary over the islands will weaken while an
amplifying trough aloft pushes another front toward/into the area
by Fri-Sat.  This trough/front will encourage the northeastward
flow of moisture currently south of the islands, with the highest
precipitable water values likely to pass over the Big Island.  The
00Z ECMWF has dramatically reduced its 12Z Thu-12Z Sat QPF totals
relative to its 12Z run and the window of opportunity appears
fairly narrow, but the pattern still appears to support the
possibility of a brief period of training/repeat activity that
could produce at least narrow bands of rainfall heavier than
indicated by GFS runs.  From the weekend into next week expect a
drying trend and a return of light to moderate trade flow with
mostly light windward focused showers as a weak surface ridge
becomes established to the north.  By next Wed trades could weaken
a bit depending on the amplitude of modest troughing aloft to the
north of the area, with the 00Z ECMWF/EC mean/CMC showing a slower
and more amplified solution leading to a slightly weaker surface
ridge.  Typical guidance error at that time frame captures both
this cluster and the GFS/GEFS runs so confidence is low in
determining which is the more likely scenario at this time.

Rausch