Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
316 AM EDT Fri Oct 23 2020

Valid 00Z Sat Oct 24 2020 - 00Z Sat Oct 31 2020

...Heavy rain possible next week...

Guidance indicates an upper low developing early next week to the
northwest of the area, dropping southward or southeastward toward
Hawai'i. The 00Z ECMWF was farthest west of the deterministic
models with this scenario while the Canadian/UKMET were farthest
east. The 00Z GFS was in the middle near much of the ensembles,
sinking it southward along 160W to just south of 30N late next
week. With a large east-west spread in the models/ensembles (on
the order of 2000+km), prefer to stay in the middle for now. This
would bring in deep tropical moisture over the island chain
(precipitable water values over 2 inches) as early as Tuesday and
perhaps continuing through the week. Several inches of rain are
possible each day in this scenario, depending on where the surface
boundary settles.

Fracasso