Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
343 AM EDT Wed Aug 28 2024

Valid 00Z Thu Aug 29 2024 - 00Z Thu Sep 05 2024

...Continuing to monitor potential effects of weakening Tropical
Storm Gilma later in the week...

Expect moderate to brisk trades and windward/mountain shower focus
Wednesday-Thursday, with an area of greater moisture ahead of T.S.
Gilma helping to enhance rainfall totals somewhat.  Guidance
clustering has improved for what remains of Gilma's surface
reflection as it nears the main islands, especially compared to
the timing spread seen 24 hours ago.  The latest forecast
continues to show a path just north of the Big Island on Friday,
and very close to the remaining islands.  Gilma's passage will
briefly disrupt the trades and associated moisture will likely
increase rainfall for a time, with specifics still very sensitive
to the exact track of the weakening surface low.  Behind Gilma,
T.S. Hector should weaken more quickly with at most a surface
trough passing through around Sunday.  Associated moisture will
cross the islands as well but a strengthening ridge aloft should
temper rainfall amounts.  High pressure to the northeast should
help to establish moderate to brisk trades once again by early
next week, followed by a weakening trend as the surface high lifts
away.  Latest models/means agree that precipitable water values
will eventually decrease to below climatology, which combined with
the upper ridge will tend to keep rainfall on the light side
early-mid week.

Rausch