Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
353 AM EDT Sun Apr 13 2025

Valid 00Z Mon 14 Apr 2025 - 00Z Mon 21 Apr 2025

Moderate to breezy easterly trades should continue over the next 
couple of days as surface high pressure remains to the north of 
Hawaii. A weak low aloft could allow for a bit of instability for 
a showery pattern, with the showers favoring windward and mauka 
areas.

High pressure is forecast to weaken and pull away Tuesday and 
beyond, weakening the trades. Winds should veer more southerly as 
a trough aloft approaches, but land and sea breezes may dominate 
the pattern with the weak background winds. The upper trough will 
push a surface cold front that stalls west of the state for the 
latter half of the week. Ahead of the front, moisture will be 
drawn northward atop the islands and increase shower coverage. 
Models vary on just how much available moisture there would be, 
with the ECMWF showing precipitable water values reaching into the
95th percentile for this time of year. Other models are not so 
aggressive but regardless a wet pattern is likely. This should
peak Wednesday-Friday, though the ECMWF and its ensemble mean 
continue the wetter pattern into next weekend. Given the trough 
aloft, there could be some heavy downpours, so continue to monitor
the forecast. By next weekend, moderate trades may resume as high
pressure redevelops well north.


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