Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
217 AM EST Thu Dec 30 2021

Valid 00Z Fri Dec 31 2021 - 00Z Fri Jan 07 2022

Rains will move in to the islands from the west by New Year's Day
as the Ridge that had been anchored north of the state for several
days begins to shift and weaken. An approaching upper trough will
drive a cold front south toward the islands which will cause the
trade winds to become more southerly. Additional rains will spread
to the windward favoring terrain as tropical moisture streams
northward. This will reinforce the precipitation, which may have
periods of moderate to heavy intensity.

Campbell