Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
216 AM EST Sat Dec 03 2022

Valid 00Z Sun Dec 04 2022 - 00Z Sun Dec 11 2022

...Closed low development just northwest of the state favors a
heavy rain threat next week...

Recent and latest runs of the GFS/ECMWF/UKMET/Canadian agree that
shower activity across Hawaii should be relatively limited through
the weekend under general upper ridging. Expect near typical
easterly trades will support some windward/mountain focused
showers.

The aforementioned models and supportive ensembles offer a similar
pattern evolution for next week, bolstering forecast confidence.
There is a strong signal to carve out a closed low/trough from the
north to just to the northwest of the islands early next week that
is slated to linger into mid-later week. This would stall a well
defined surface front just west of the islands and lead to a shift
to southeasterly/southerly trade winds into the islands with
increasingly deep and sustained moisture inflow to fuel a period
favorable for some heavy downpours that may lead to local runoff
issues. High pressure building strongly in guidance to the
northeast of the state in the wake of closed lo departure later
next week into next weekend should then support a return to more
typical moderate to breezy easterly trades and revert to a pattern
with more limited and windward terrain focusing showers.
 
Schichtel