Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
354 AM EDT Sun Mar 23 2025

Valid 00Z Mon 24 Mar 2025 - 00Z Mon 31 Mar 2025

Today's guidance maintains good agreement and continuity through
most of this week. Trades will be fairly light Sunday-Monday as an
approaching front ultimately stalls just north of the main 
islands. Consensus maintains the recent theme of frontal waviness
generating an axis of heavy rainfall a ways northwest/north of 
the main islands early-mid week, while trades rebound somewhat 
from Tuesday onward in easterly or southeasterly fashion. This 
pattern should bring a return of windward showers, though likely 
with fairly light totals as a strong upper ridge builds in from 
southeast late this week.

Guidance has shown more spread and variability with the forecast
for this weekend. Latest GFS/GEFS runs have at least adjusted
their previously over-amplified east-central Pacific upper trough
enough to maintain easterly trades during the weekend. Machine
learning models generally suggest that the GFS/GEFS may still be
too weak with the upper ridge over the islands though. By Sunday,
differences with evolution of a system well to the west or
northwest affect the orientation of island winds. ML models differ
enough to allow for a range of possibilities between the more
southerly winds in the 00Z ECMWF/CMC or easterly in the GFS. The
ensemble means support persistence of the easterly to
southeasterly winds, which appears the most reasonable approach
until a more dominant alternative cluster arises.

Rausch