Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
201 AM EST Mon Dec 05 2022

Valid 00Z Tue Dec 06 2022 - 00Z Tue Dec 13 2022

...Kona low development just northwest of the state favors a
early-midweek heavy rain threat...

The GFS/ECMWF/UKMET/Canadian models and supportive ensembles offer
a similar pattern evolution for the coming week, bolstering
forecast confidence. There is a strong signal to carve out a Kona
low to settle just to the northwest of the islands early week and
linger into midweek before ejecting northwestward away from the
state. A well defined surface front stalls just west of the
islands early week and a lead shift to southeasterly/southerly
winds into the islands will bring increasingly deep and sustained
moisture into the state. This will 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 week into next
weekend should then support a return moderate to breezy easterly
trades and revert to a pattern with more limited moisture and
windward terrain focusing showers under an amplifying upper ridge.
There is a growing guidance signal to monitor that shows
separated/closed low energy working southwestard and underneath
the upper ridge to just south of the islands late weekend into
early next week that if manifested could renew some shower fueling
moisture back into the state.
 
Schichtel