Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
157 AM EST Sat Dec 6 2025

Valid 00Z Sun 07 Dec 2025 - 00Z Sun 14 Dec 2025

A cold front in association with a deep trough and cutoff low 
west of the state should weaken and retrograde as an easterly wave
this weekend. Winds should moderate back to normal easterly 
trades this weekend with the usual windward shower paradigm 
expected. A compact cut off low will meander east and northeast of
the state as late as Wednesday but is forecast to have minimal, 
if any, impact on precipitation amounts across Hawai'i before it 
moves east, out of the picture. 

Another cold front moves into the western main islands late Wednesday
at the leading edge of a positively tilted trough. While timing 
is no longer a factor, the guidance now allows the front to sweep
cleanly through the main Hawaiian Islands by next Saturday. There
is some difference as to where a closed/occluded low sets up 
within the trough, with the GFS a bit farther south with its 
cyclone which could bring cooler/drier air across the state. A 
compromise position for the deep layer low, north of the 00z GFS,
is currently preferred. In any event, moderate to heavy 
showers/thunderstorms are expected to accompany the frontal 
passage, though expected rainfall doesn't appear to be excessive 
at the present time as the front is forecast to be progressive.

Roth