Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
712 AM EST Sun Dec 09 2018

Valid 00Z Mon Dec 10 2018 - 00Z Mon Dec 17 2018

Today's guidance continues to show that high pressure centers
tracking to the north of the state will support fairly strong
trades during most of the period.  Expect windward focused showers
that may stray into leeward locations at times, with amounts
tending to be in the light-moderate part of the spectrum as
precipitable water remains below climatological values through the
period.  A couple bands of moisture, along and behind a front now
dissipating over the state, may provide modest enhancement to
rainfall early this week.  Most models show a weak upper level
circulation tracking from northeast to southwest across the main
islands around Tuesday-Wednesday, and this may provide a little
enhancement to shower activity as well.  The small scale of the
feature lends itself to below average predictability.  Models vary
in specifics but generally agree that moisture should decrease a
bit in the late week/weekend time frame. 

Strongest trades should exist late Sunday into Tuesday followed by
a slight midweek relaxation of the pressure gradient as a front
passes by to the north.  The trailing surface high may strengthen
trades a little Thursday-Friday.  From late Friday into the
weekend most guidance suggests that another high center may form
in the western part of the overall surface ridge and sink
southward and then east-southeast closer to the state.  As this
occurs the high is gradually weakening so the trades may be stable
in spite of the closer proximity of high pressure.  By later next
Sunday the high may reach far enough eastward to yield lighter
winds.

Rausch