Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
745 AM EDT Sun Sep 18 2016

Valid 00Z Mon Sep 19 2016 - 00Z Mon Sep 26 2016

The models and ensembles show a low level ridge building north of
the islands with a steadily drier trend today into midweek.  With
this drier trend precipitable water values should decrease down to
1-1.25".  The GFS and ECMWF show a tropical wave passing through
the latter half of the week, with a resultant return to higher
moisture values once the wave passes.  Both model suggest another
low level ridge builds north of the islands next weekend, with
another reversal towards drier conditions in the column.  Moderate
trades are expected except weakening when the tropical wave is in
the vicinity.  Showers will mostly be windward focused except when
the wave passes when showers could occur anywhere.  The
models/ensemble means appear to be in good agreement on the large
scale pattern.

Petersen