Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
818 AM EDT Mon Apr 17 2017

Valid 00Z Tue Apr 18 2017 - 00Z Tue Apr 25 2017

High pressure across the Hawaiian Islands is expected to persist
Tue and into Wed before a weakening cold front approaches the
northern/western islands by Wed night ahead of an upper low
centered along 40N. Easterly flow of 20 kt will veer to light
south-southwesterly ahead of the front. Precipitable water values
will increase across the western islands into the 1.25-1.5 inch
range along/ahead of the front, and some showers are anticipated
as the front washes out across the western/central islands through
Friday night. From Friday onward, models show good agreement on
mid/upper-level ridging expanding across the central Pacific, with
the westerlies shifting northward and low-level easterly flow
re-establishing itself across Hawai'i. Isolated showers may
persist as whatever is left of the washed out surface front
lingers for a few days before drier air advects in on the easterly
flow by early next week. Deterministic models and ensembles show
generally good agreement with respect to these features across
Hawai'i over the next week

Ryan