Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
359 AM EDT Sun Sep 11 2022

Valid 00Z Mon Sep 12 2022 - 00Z Mon Sep 19 2022

Another day of light to moderate trade winds are forecast for
Sunday, promoting a hybrid pattern of localized land/sea breezes
and trades and thus some clouds and showers possible in windward
areas but also in leeward/interior areas where sea breezes set up.
By Monday the trade winds should strengthen somewhat to moderate
levels as a more typical surface pressure gradient builds in with
highs north of Hawaii, causing showers to focus more in windward
areas. Meanwhile aloft, a trough over the western part of the
state and ridge to the east will lead to deep layer southerly
flow, directing deep tropical moisture northward toward the state
beginning as early as Monday. Model guidance generally agrees now
that while the highest moisture levels (e.g. precipitable water
values of 2+ inches) are likely to stay south, some above average
moisture is likely to reach at least the Big Island and perhaps as
far north as Oahu. With the moist environment in place, some
increased clouds and showers are possible especially in windward
areas through around Wednesday. Troughing aloft in Kauai should
lift inversion heights and promote rainfall potential there as
well. Moderate trade winds and perhaps a slightly drier pattern
are expected later in the week over the state.

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