Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
257 AM EST Sat Feb 17 2024

Valid 00Z Sun Feb 18 2024 - 00Z Sun Feb 25 2024

A relatively cool and dry airmass is in place across the state
behind a cold front, with north-northeasterly winds. Onshore flow
to the northeastern side of the Big Island may produce some
ongoing showers into Saturday per the HREF, but precipitation is
not expected elsewhere Saturday. A surface high will track
eastward to the north of the state (centered around to just north
of 30N) through the weekend into early next week. This will help
cause winds to gradually veer to northeasterly this weekend and to
a more typical easterly direction early next week. These trades
may have some variations in speed from day to day, but look to be
generally moderate to breezy. Drier than normal precipitable water
values are likely to remain in place through the first half of
next week, but some showers may affect favored windward and
mountain areas under easterly flow. The atmosphere looks to
gradually moisten late next week while upper and surface lows
develop well west of the islands. Model guidance varies with how
close the surface low/frontal system edge toward the state by late
week. The ECMWF/CMC bring the moisture plume just ahead of the
front east and spread heavy rainfall amounts close to the
northwestern islands, while the GFS stays well west, and ensemble
members vary. Confidence is low at this point but the forecast
will continue to be monitored.

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