Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
218 AM EST Fri Jan 17 2025

Valid 00Z Sat Jan 18 2025 - 00Z Sat Jan 25 2025

Through the weekend at least, the guidance continues to show good
agreement on with a frontal passage into Today, with some
potential for moderate to locally heavy rainfall, although highest
totals should remain well to the north of Hawaii. High pressure
behind this front in conjunction with a weaker trailing front to
the northwest will likely bring moderate to brisk northeasterly
winds for the weekend into early next week. Below-normal
precipitable water values behind this late week front should keep
most showers fairly light through the weekend.

By Tuesday and onward, models continue to show some significant
differences with an amplifying upper trough and leading cold
front. The latest GFS run remains quite a bit faster and less
amplified than the ECMWF and the CMC, but the CMC is by far the
slowest and most inconsistent with the ensemble means. The ECMWF
is a nice middle ground solution and fits closest to the ECENS and
GEFS means, and a combination of this guidance would be the
preferred solution at this point. In terms of sensible weather,
this makes the difference between a slower/wetter frontal passage
around Wednesday/Thursday in the ECMWF cluster versus a
faster/drier one in the GFS, with trailing high pressure restoring
trade flow more quickly.

Santorelli