Prognostic Meteorological Discussion
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360
FXHW01 KWNH 170735
PMDHI

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
335 AM EDT Thu Apr 17 2025

Valid 00Z Fri 18 Apr 2025 - 00Z Fri 25 Apr 2025


A trough aloft is currently atop Hawaii and should remain over
the state through late week. At the surface, troughing in place is
disrupting the trades. Winds are forecast to stay weak in most
areas and allow for land and sea breezes to dominate the pattern.
Meanwhile a weakening front will stall to the west, ahead of which
moisture will be drawn northward atop the islands and increase
shower coverage. Precipitable water values could be near or over
the 90th percentile for this time of year, while the upper trough
could allow for some instability to form to support potential
thunderstorms. Thus a wetter pattern is likely on Thursday and
Friday, with showers and storms likely peaking over the islands
during the day because of sea breezes.

Over the weekend, the upper trough is forecast to weaken and pull
away, while Pacific surface high pressure develops well north and
allows for trades to gradually resume. This may be a somewhat wet
trade wind pattern through early next week as moisture lingers.
Then by around the middle of next week, another upper trough is
forecast to dig west of the state. This will once again cause the
mean flow to veer for southeasterly/southerly winds that may be
stronger this round. Moisture and showers are likely to increase
once again as well.


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