Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
226 AM EST Thu Jan 14 2021

Valid 00Z Fri Jan 15 2021 - 00Z Fri Jan 22 2021

A couple of weak fronts moving into the region late this week will
provide brief disruptions to the trades and increased showery
activity. By late Sunday, there continues to be good agreement
that a more defined/amplified shortwave will approach Hawaii,
driving a strong cold front southward, which reaches Kauai around
Sunday-Monday. Both the operational GFS and ECMWF continue to show
enhanced rainfall associated with this front as it passes through.
Guidance also indicates troughing/low pressure lingering over or
near the islands into the middle of next week, which may help draw
deeper tropical moisture northward. Both the 00z ECMWF and 00z CMC
show a closed low lingering just west of the states which results
in heavy rainfall across the Big Island during the middle of next
week. The 00z GFS however, keeps the troughing east of the state
which also would keep the heaviest rains well offshore. Needless
to say, uncertainty with any kind of heavy rainfall over the state
around Wednesday of next week is very high, but the models have
been fairly consistent on showing the potential is there, it just
depends exactly where the better moisture feed sets up.

Santorelli