Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
807 AM EDT Sat Jun 27 2015

Valid 00Z Sun Jun 28 2015 - 00Z Sun Jul 05 2015

Guidance continues to show a generally retrogressive evolution of
the Pacific mean pattern over the course of the next week.  Within
the mean trough to the north of the state, the combination of a
leading wave reaching as far south as 35N and then a
deeper/farther northward system will support a break in surface
high pressure.  Thus expect somewhat weaker trades from this
weekend into early next week.  Guidance continues to indicate that
the evolution of mean flow aloft will support a westward building
of eastern Pacific high pressure from Wed onward, bringing a
return of moderate trades in that time frame.  Note that from Tue
onward the 00z ECMWF is on the more amplified side of guidance
with the trough aloft.  As a result it is more pronounced with its
surface reflection to the northwest/west of the state and slower
to build the eastern Pacific ridge westward.  Prefer a compromise
among other guidance for this aspect of the forecast.

Relative weakness of trade flow this weekend into early next week
should provide some land/sea breeze influence on shower activity
with windward locales likely gaining a greater focus from midweek
onward.  Some enhancement of rainfall is possible with the passage
of a tropical wave in the Tue-Wed time frame.  Associated higher
precipitable water values may linger to some extent into Thu-Fri
before trending a little lower.  

Rausch