Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
320 AM EDT Thu Mar 18 2021

Valid 00Z Fri Mar 19 2021 - 00Z Fri Mar 26 2021

Lingering upper troughing will hold over the region through the
weekend in advance of a digging upper low next week. Surface high
pressure will move eastward just north of 30N this weekend,
maintaining breezy northeast trades. With precipitable water
values around 0.8-1.2 inches and middle atmospheric moisture
(400-700 RH) fairly low, only light windward and mauka showers are
expected for the next few days. By next Tuesday, 00Z guidance
shows a digging upper low near 35N/162W that may linger in that
area for a couple days. This could act to weaken trades and veer
to a southerly component as moisture increases from the south.
Cold front associated with the surface low may slip southeastward
toward at least the northwestern islands next Wednesday and stall
on Thursday. More appreciable rainfall is possible by the middle
of next week. Ensembles show good agreement overall on the upper
features but more spread on how much moisture and rainfall may be
realized over the 50th state. Prefer a consensus solution at this
point.

Fracasso