FXHW01 KWNH 210854

PMDHI 



Hawaii Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

454 AM EDT Sun Jun 21 2026



Valid 00Z Mon 22 Jun 2026 - 00Z Mon 29 Jun 2026



Forecast remains on track as an upper-level trough located to the

north of the islands start of the period and a surface front 

positioned well to the northwest. This will combine to disrupt 

the typical trade wind inversion, resulting in light surface winds

across the region for the next day or so. As the initial upper 

trough continues to be positioned to the north of the state, the 

surface boundary is expected to remain in place and drift closer 

to the islands as shortwave energy moving through the westerlies 

provides upper- level support to amplify another trough north- 

northeast of the state by Tuesday. This configuration may favor a 

shift to a more northeasterly flow over the islands early this 

week. By Wednesday through the remainder of the forecast period, 

the aforementioned trough is expected to become cut off and sink 

southward as the subtropical jet also lifts north. This may lead 

to additional rain chances through late week, as highlighted by 

the ECMWF EFI QPF variable with some low values (0.5-0.7) for

Wednesday into Thursday. Additionally, an increase towards more

typical trade winds can be expected as well.



Snell