Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
756 AM EDT Sat Sep 02 2017

Valid 00Z Sun Sep 03 2017 - 00Z Sun Sep 10 2017

A low level ridge persists northeast of the islands through the
weekend.  To the northwest of the islands, a slowly approaching
cold front is forecast to only slowly drift southeast towards the
islands or even stall into next week.  The consensus is the front
actually weakens and not actually make it into the islands during
the middle portion of next week.
Scattered showers and thunderstorms are forecast each day. 

During the middle and latter portions of next week, the
models/ensemble means are in better than average agreement on the
low level high building north of Hawaii.  Trades should then
return to near normal levels during this middle to latter portions
of next week. Both the gfs and ecmwf show a tropical wave moving
south of the islands mid to late next week. The current rainfall
forecasts show the higher amounts remaining south of the islands. 
The higher available moisture does support the possibility of
locally heavy downpours later next week.

There remains better than average agreement among the 06z gfs and
00z ecmwf 700-500 mb forecasts next week to use a blend of the two
to mitigate differences.

Petersen