Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
704 AM EDT Sun Jun 21 2015

Valid 00Z Mon Jun 22 2015 - 00Z Mon Jun 29 2015

The latest guidance maintains good through Friday, before
differences begin to appear between the 06z GFS and 00z ECMWF with
the handling of a trough near 155W.  The ECMWF shows greater
amplitude, though this does not seem to impact the front/shear
line extending towards the Papahanaumokuakea Marine National
Monument early Saturday.  Overall, the trades are steady into
Thursday before a temporary weakening occurs late Thursday into
next weekend as the shear line approaches the main islands. 

There are skirmishes of higher moisture (precipitable water values
>= 1.50") early this morning associated with a surge in the trade
winds, and then again Monday night as an easterly wave/upper low
retrogrades from 146W early this morning into the Big Island. 
Saturday night/Sunday another increase in moisture was noted near
160W.  Each of these moisture intrusions could lead to a
enhancement to the normal windward shower regime.

Roth