Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
811 AM EDT Mon Mar 16 2015

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

Into midweek expect winds to be on the light side as the state
should be located near an elongated surface ridge on the extreme
western periphery of weak eastern Pacific high pressure.  The
light prevailing winds may allow for more than the usual influence
from land and sea breeze boundaries on shower activity, which
should be light given precipitable water values near or a little
below an inch.  Guidance remains agreeable that a front will reach
the islands around Wed night-Thu but supported by fairly week
dynamics and accompanied by only a modest increase in moisture. 
Thus rainfall with the front should be light.

Behind the front trailing high pressure will bring stronger
northerly to northeasterly winds by Thu, with winds remaining
northeasterly for the rest of the period as one surface high cell
breaks off to the north/northeast of the area Fri and remaining
high pressure drifts to the north/northeast of the islands next
Sun-Mon.  From Fri onward there is a general consensus toward a
gradual further increase in moisture with PWATs reaching at least
1.25 inches at some locations, so windward focused rainfall may
become a little more enhanced Fri-Mon.  The best potential for
this enhancement is over the Big Island corresponding to best
agreement for highest PWATs.  By next Sun-Mon the 00z ECMWF shows
higher than consensus heights aloft over/northeast of the islands
so would lean away from its solution for that aspect of the
forecast.  However there is still spread among remaining guidance
as to the northwestward extent of best deep moisture, with low
predictability of important smaller scale details at the day 6-7
time frame recommending a compromise approach for now.

Rausch