Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
240 AM EST Mon Dec 19 2022

Valid 00Z Tue Dec 20 2022 - 00Z Tue Dec 27 2022

An anomalous closed upper low, with a 990-mb surface low sinking
just south of 30 degrees north, will continue to be a very
impactful weather event through Tuesday.  A tight pressure
gradient with the low will produce high winds gusting well over 40
mph at times, and even hurricane force winds for the higher
summits Monday afternoon and into Monday night.  These
southwesterly winds will then veer to the west and northwest once
the strong front moves through, and will continue to be quite
breezy through Tuesday night before abating and becoming more
variable going into the middle of the week. 

The heavy rainfall from the storm system in the short range is
forecast to move out of the state by Tuesday afternoon with some
lingering showers across the windward terrain, and snow for the
Big Island summits.   This low pressure system then lifts
northward by midweek, with a weak surface high building in across
the Islands by the end of the week and into the weekend.  Another
cold front may approach the northwestern Islands on Friday, but
not as strong as the ongoing event.  Drier conditions can be
expected for most locations for Wednesday and beyond except for
terrain enhanced showers across the Big Island as a more typical
trade wind pattern tries to return by the end of the week,
although weaker flow than normal for most days.
 
Hamrick