Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
351 AM EDT Tue Oct 18 2022

Valid 00Z Wed Oct 19 2022 - 00Z Wed Oct 26 2022

One more day of light trade winds is expected Tuesday, allowing
for a land and sea breeze pattern to set up over Hawaii once
again. Shower coverage is likely to be somewhat limited with
ridging aloft leading to a stable airmass. But a more active
pattern is likely to begin around Wednesday, as upper troughing
moving across the Pacific splits energy off into a closed upper
low by late Wednesday to the north of the state (around 30-35N
before drifting southwestward). Meanwhile at the surface, a cold
front is likely to track across the northern islands and stall.
This front will bring some breezy northeasterly winds behind it as
well as provide a focus for moisture and increased coverage of
showers for Wednesday-Friday, with the exact positioning of the
front's meandering determining where the highest rain totals could
be. Kauai and Oahu to perhaps Maui appear most likely for
increased shower activity, but a moist airmass should be in place
farther south as well for some shower potential, particularly in
favored sea/land breeze areas. As the upper low drifts west, so
will any remains of the front. But a moist environment could
return next weekend with moisture being pulled north from the
ITCZ. This potential for increased moisture is most agreeable for
the Big Island but some guidance like the ECMWF shows the moisture
reaching most of the state. By early next week, a more stable
pattern is forecast to build in, reducing rain chances, while
trade winds strengthen as a surface high develops north of Hawaii
once again.

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