Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
515 AM EDT Sun Oct 4 2026

Valid 00Z Mon 05 Oct 2026 - 00Z Mon 12 Oct 2026

Subtropical ridge will remain in control across the Islands from 
the north through early next week. This will result in the more 
typical east-northeasterly trades with a drier, more stable 
airmass this weekend and through Tuesday. Shower activity 
(coverage) during this time will become more limited -- confined 
to favored windward mountain areas.

By the middle and latter part of next week, a mid-upper trough 
will amplify west of the state, which will eventually disrupt the 
trades and cause the deep-layer flow to veer more southerly. As 
this occurs, tropical moisture (PWATs 1.75-2.00") will be drawn up
across the state, especially across the western and central 
Islands. The global models (GFS/ECMWF/CMC) do exhibit differences 
with the amplitude and timing of the mid/upper level trough by
late next week, which would have an influence on the eastward 
extend of the moisture resurgence across the Islands, and to what 
degree rain chances/coverage will increase by midweek into next 
weekend. 

Hurley