Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
245 AM EST Fri Feb 28 2020

Valid 00Z Sat Feb 29 2020 - 00Z Sat Mar 07 2020

...Heavy rain possible this weekend into next week...

Troughing to the northeast of the area will eventually form a
closed low that will move westward across the islands late
Sat-Mon, weakening thereafter as it moves northwestward and
northward around an upper high to the northeast then east. The
latest suite of model guidance shows good agreement with this
evolution, but still vary on the associated QPF placement and
amounts. At the surface, models continue to show a ~1040mb high
settling well north of the state, and the resulting strong
pressure gradient across Hawaii will yield breezy trades through
the weekend, and possibly into early next week. By the middle of
next week, heights should begin to rise back above average.

The upper low will bring a cold/unstable airmass across the
region, possibly supporting convection and the potential for snow
in some of the higher terrain. Several inches of rain are possible
as the upper low passes through, but guidance continues to show
the heaviest precipitation staying just offshore to the east.
Regardless, there is potential for deep tropical moisture to get
pulled over the area, so the heavy rain threat remains, with
highest probabilities over the Big Island. By mid to late next
week, with the upper low likely disintegrated and heights rising,
rainfall amounts and coverage should decrease.


Santorelli