Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
803 AM EDT Fri Mar 13 2015

Valid 00Z Sat Mar 14 2015 - 00Z Sat Mar 21 2015

The islands will continue to see a drying trend at the start of
the period as an upper trough and leading surface front continue
eastward.  High pressure to the northwest of the state will
support brisk northerly winds that will trend more northeasterly
by Sat.  Expect trades to slacken gradually as the surface high
weakens and becomes more elongated.  Windward showers will likely
be light with precipitable water values under 0.75 inch through
the weekend and increasing only to around an inch for the first
part of next week.

There is reasonable agreement from the guidance that a front
should approach the region around Wed, and then weaken and/or
progress eastward to some degree thereafter.  Confidence in
specific solutions decreases after Wed as individual model runs
and ensemble members diverge with respect to how shortwaves evolve
within progressive and low amplitude Pacific flow.  However the
amplified trough aloft passing to the north/northeast of the state
Thu-Fri in the 00z GFS differs most from other guidance at this
time.  Therefore would recommend one or more of the 06z GFS, 00z
GEFS mean, or 00z ECMWF/ECMWF mean as a starting point for the
Thu-Fri forecast.  Modest dynamics and little increase in deep
moisture suggest that any rainfall associated with the front
should be in the lighter half of the spectrum.  Expect trade flow
to become better established once again late next week after
weakening/passage of the front.

Rausch