FXHW01 KWNH 100554
PMDHI

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
154 AM EDT Sat Oct 10 2026

Valid 00Z Sun 11 Oct 2026 - 00Z Sun 18 Oct 2026

Our potent mid to upper low to the northwest of the Island will 
continue a slow propagation over the Central Pacific before 
weakening significantly this afternoon through Sunday with the 
disturbance fully decayed by the end of the weekend. PWAT 
anomalies will return closer to normal by the end of the weekend
lending to a return to a more climatological convective setup,
especially for the western half of the island chain.

Sunday into early next week will see a small break in the heavy
rain prospects, but a weak disturbance stemming from a pinched off
mid-level vorticity stream to the northeast will meander to the
west with a close proximity to the island come Sunday afternoon
through early Tuesday. This could trigger a bit more of a
convective threat over the Big Island on these days, but not
anticipating anything significant given the less than formidable
PWATs in place. Greatest threat is likely Monday into Tuesday
before the longwave pattern over the Pacific changes and we see a
return to a typical trade-wind pattern over the region as broad
ridging returns to the North Pacific. Some modest moisture fluxes
will ripple through the prevailing easterly flow triggering slight
convective enhancements to the windward side of the islands,
albeit nothing substantial at this juncture. 

Kleebauer

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