Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
710 AM EST Sat Nov 26 2016

Valid 00Z Sun Nov 27 2016 - 00Z Sun Dec 04 2016

A surface high initially to the north/northeast of the state
followed by another high passing well north of the islands around
Tuesday will support fairly brisk trades through midweek.  During
this time frame expect shower activity to be mostly in the lighter
half of the spectrum with precipitable water values near to below
normal. 

By later in the week and next weekend expect an increase in
moisture/rainfall but with some uncertainty as to extent and
coverage.  Sheared upper level energy dropping southeastward
across the area Tuesday-Wednesday may at least partially combine
with upper low energy farther east to yield an upper circulation
near or just east of the islands.  This feature combined with
upstream trough energy that may amplify late in the period should
lower surface pressures and draw increased moisture into at least
the southeastern islands.  Current guidance shows meaningful
differences in position of not only the mid-late week upper low
but also longitude of upstream amplification.  On both counts the
00z ECMWF/CMC and their corresponding ensemble systems suggest a
farther westward position than the 00z GFS/GEFS and 06z GFS. 
Average guidance error 5-7 days out in time tempers confidence in
a specific solution, however at this time it would be reasonable
to expect potential for more moisture to reach the islands from
the southeast, and a farther westward extent of it, relative to
latest GFS/GEFS runs.

Rausch