Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
334 AM EDT Tue Aug 08 2023

Valid 00Z Wed Aug 09 2023 - 00Z Wed Aug 16 2023

Very strong winds over the state on Tuesday, due to the tight
gradient between deep-layer ridging to the north and Hurricane
Dora tracking to the south, should slacken toward moderate trades
by the latter half of the week and into next week.  The westward
progression and weakening of the ridge will initially support the
weaker trend.  Then an elongating upper weakness, likely
containing one or more lows, should pass over or near the state
from the northeast and further weaken the pressure gradient.  By
Sunday-Tuesday the GFS/GEFS mean again maintain a slightly
stronger gradient than most other models/means.  Guidance
continues to depict an east-west axis of relatively dry air across
the state during the period, with the most anomalously low
precipitable water values around Tuesday-Wednesday and then
gradually rising to less extreme (but still below normal) values
thereafter.  By next Tuesday the 00Z GFS shows the northern
periphery of lower latitude moisture reaching the Big Island but
the 00Z ECMWF and the 00Z GEFS/12Z ECMWF mean are less
enthusiastic about that idea to varying degrees.  The general lack
of moisture should yield fairly light windward focused showers,
with amounts possibly increasing a little by the weekend and early
next week with the upper feature from the northeast likely passing
overhead.

Rausch