Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
231 AM EDT Sat Oct 18 2025

Valid 00Z Sun 19 Oct 2025 - 00Z Sun 26 Oct 2025

The main surface high will be situated well to the north of Hawaii
this weekend, with the typical easterly trade wind pattern over
the Islands through the early part of the week. The ensemble means
are hinting at a weak inverted surface trough developing over the
state Wednesday into Thursday in response to a broad upper trough
over the region. The surface high then rebuilds closer to the
Islands to close out the week.

Normal coverage of showers across the windward terrain can be
expected on most days. It currently does not appear that the mid-
week trough will be strong enough to advect deeper moisture from
the ITCZ, so therefore no major rainfall events are anticipated
based on the latest model guidance.

Hamrick