Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
112 AM EST Fri Dec 16 2022

Valid 00Z Sat Dec 17 2022 - 00Z Sat Dec 24 2022

An upper low initially centered well to the north of Hawaii will
allow for a cold front to approach the islands, advecting tropical
moisture northward and increasing rainfall chances to close out
the work week.  A blocky upper ridge anchored in place over the
eastern Pacific will result in this low moving northward and away
from Hawaii.  However, the next upper low/trough gets even closer
to the islands on Monday with a second cold front impinging upon
the state.  This is expected to result in gusty southerly winds
veering to the west and then northwest, and increasing prospects
for periods of heavy rainfall for the early to middle part of next
week along and ahead of the front.  There still remains some
uncertainty in the details of this system which affect both timing
and more precise rainfall amounts, though both the GFS and ECMWF
show the potential for 2 to locally 5 inches of rain for some of
the larger islands.  This low pressure system then lifts northward
by midweek, with a weak surface high trying to build in across the
Islands by the end of the week.  The cold front should move east
of Hawaii around Wednesday-Thursday next week with drier
conditions to follow, with generally light southeasterly winds.
 
Hamrick