Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
828 AM EDT Tue Oct 03 2017

Valid 00Z Wed Oct 04 2017 - 00Z Wed Oct 11 2017

The latest satellite imagery shows an upper low and surface front
now situated just west of the westernmost Hawaiian Islands. Models
and ensembles continue to show good agreement that this low will
continue drifting westward away from the islands. In its wake,
models continue to advertise upper level ridging expanding across
the state allowing for dryer weather and rather brisk easterlies
of 20 to 30 knots lasting through the rest of this week.

By late this week, an amplifying upper level trough across the
northeast Pacific is forecast by all deterministic and ensemble
guidance to cut off into a deep upper low near 140 west, and drift
west-southwestward before becoming absorbed into troughing to the
north by early next week. Even though the upper low should remain
well to the northeast of Hawaii, the resultant falling heights
across the central Pacific should push a cold front southward
towards the islands by Friday or Saturday. Along with weakening
trades backing to more north-northeasterly, a modest increase in
PWATs looks to accompany the front. Expect showery activity to
increase across the islands by the weekend with some locally
enhanced activity possible along the front. Trades should return
to more easterly by next week, but showery activity may stick
around as the front briefly stalls across the islands early to
middle of next week.

Santorelli