Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
136 AM EDT Tue Jun 16 2026

Valid 00Z Wed 17 Jun 2026 - 00Z Wed 24 Jun 2026

A pair of weak surface troughs; one tracking south of Hawaii and
another caught between two subtropical highs to the north, will 
gradually begin to weaken trade winds late Tuesday and into 
Wednesday. The surface trough to the south will usher in elevated 
PW anomalies that deliver additional moisture in an environment 
that will be more suitable for sea breeze development. This setup 
should lead to daily rounds of showers and even a thunderstorm or 
two over the higher terrain through mid-week, along with added
cloud cover through the end of the week. As the surface trough to
the north weakens and the subtropical ridges to the north over 
power the trough, the pressure gradient will restrengthen by this 
weekend and a strengthening field of trade winds will return. Not 
only will the more moderate trade winds return for the weekend and
early next week, but the elevated moisture over the state will 
exit to the west, leading to slightly better chances for upslope 
showers along the windward sides of the Island Chain and drier 
conditions in lee of the mountains.

Mullinax