Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
203 AM EST Thu Jan 21 2021

Valid 00Z Fri Jan 22 2021 - 00Z Fri Jan 29 2021

The overall weather pattern across the Hawaii domain will be
featured with a strong mid-latitude high building in around 40
degrees north through the upcoming weekend.  This will tend to
strengthen the trades with a mainly easterly component to the
flow, and then veers more towards the southeast by Sunday.

By Saturday night, an inverted surface trough is progged to
develop near 170 degrees west in response to a weak upper low,
with most of the rain from this event expected to be west of the
Islands.  However, locally heavy trade wind based showers are
likely across the favored terrain of the Big Island early next
week.  By Wednesday, there are signs of a larger scale trough well
to the northwest of the state, but the specifics are more
uncertain with the GEFS mean well to the east of the EC mean.

Hamrick