FXHW01 KWNH 220801

PMDHI 



Hawaii Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

401 AM EDT Sun Mar 22 2026



Valid 00Z Mon 23 Mar 2026 - 00Z Mon 30 Mar 2026



...Flash flood threat to continue into Monday across Hawai'i...



The pattern aloft remains troughy over the archipelago during the

next week, with mid-level ridging making some strides towards 

longer term rebuilding over the Papahanaumokuakea Marine National 

Monument late in the week. 



Initially, a deep layer cyclone to the north is working in tandem

with low level ridging east of Hawai'i to maintain an atypical 

southwest flow regime into Monday. Above average precipitable 

water values are placed favorably beneath diffluent upper level 

winds. Combined with favorable upslope ascent into southwest-

facing terrain, excessive rainfall rates will remain in the 

forecast into Monday as the cyclone's front edges eastward 

through the main islands and the low pressure system lifts 

northeast. With soils saturated and flooding ongoing, Hawaii 

remains vulnerable to additional life- threatening flash flooding 

and landslides.



As surface ridging begins to build in late Monday onward to the 

north and northeast, the anomalous moisture plume will

weaken/shift away. This is will decrease rainfall amounts and 

rain chances through the remainder of the week and return Hawai'i 

to their more typical trade wind/upslope shower regime.





Roth