Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
701 AM EST Fri Dec 21 2018

Valid 00Z Sat Dec 22 2018 - 00Z Sat Dec 29 2018

Trade winds are expected into the weekend as high pressure settles
to the northeast of the state and an upper level low retrogrades
in from the east. This pattern only supports limited windward
showers through Monday. However, there is an increasing guidance
signal supporting wetter pattern development from Tuesday onward
as a pair of shortwave troughs move by to the north lures the
upper level low through Hawai'i and a cold front approaches the
main islands while transiting the Papahanaumokuakea Marine
National Monument from Tuesday onward.  A favored composite of
reasonably well clustered models and ensembles indicates that
deeper moisture may return in advance of an approaching surface
front.  For now, the 06z GFS appears to be a slow and amplified
outlier from Thursday afternoon onward when compared to the other
guidance and is given limited weight.

Roth/Schichtel