Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
431 AM EDT Sun May 31 2026

Valid 00Z Mon 01 Jun 2026 - 00Z Mon 08 Jun 2026

An upper low just south of the Aleutians will slowly move 
eastward through the period, favoring a mid-level weakness in the 
subtropics near and just east of Hawaii. In between, around 30N, 
building heights will form an upper high by midweek that will then
weaken into next weekend. At the surface, weak pressure gradient 
will favor lighter trades through Monday and seabreeze-driven 
showers before the strengthening high to the northeast acts to 
increase trades Tuesday into next weekend. 

Though deep moisture will remain south of the area through the 
week, precipitable water values associated with a tropical wave 
will increase from the southeast on Monday as an upper jet streak 
moves through. This will favor some modest to perhaps locally 
heavier rain over at least the Big Island (potentially into Maui 
and Molokai/Lanai), before the moisture surge exits the region 
early Wednesday. Thereafter, windward/mauka showers are likely for
the rest of the week with some leeward spillage amid breezy 
trades.

Fracasso