Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
255 AM EST Wed Dec 11 2024

Valid 00Z Thu Dec 12 2024 - 00Z Thu Dec 19 2024

Today's models and ensembles show good agreement and continuity
with the overall forecast.  Expect brisk to windy trades during
Wednesday-Thursday when high pressure to the north/northeast of
the state is strongest.  Then a series of fronts will weaken the
surface ridge and and push it south, to the point of the east-west
ridge axis reaching the main islands by next Wednesday.  Thus
trades will begin to moderate after Thursday, ultimately
transitioning to light and variable winds by next Tuesday or
Wednesday.  Corresponding to this pattern change, shower focus
will be primarily over windward/mountain areas from today into
next Monday followed by more sea breeze influence.  Guidance
continues to show the highest rainfall totals during
Thursday-Friday when the Big Island in particular will be on the
northern fringe of an area of enhanced precipitable water values
associated with a retrograding low-latitude upper low.  Expect
moisture to decrease below climatological values by the weekend,
favoring much lighter showers.  With typical differences in timing
and magnitude, guidance suggests a gradual increase of moisture
from the southeast by next Tuesday-Wednesday.  However rainfall
should remain fairly light given strong ridging overhead.

Rausch