Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
819 AM EDT Fri Sep 21 2018

Valid 00Z Sat Sep 22 2018 - 00Z Sat Sep 29 2018

Upper ridging will linger over the state this weekend underneath a
pair of closed lows developing to the northwest and northeast of
Hawaii. Modest moisture and trades favor light mauka/windward
showers. A favored composite of the latest models and ensembles
now reasonably agree that the upper low to the northeast will
weaken next week as reinforcing energy digging to the lee of
western Pacific upper ridging digs ernestly into the trough
position to the northwest of the state to form a deep closed low.
This seems reasonable given high ampltide of upstream ridging in
guidance. This sets the stage for deep return moisture response
from the tropics to the islands and the potential development of a
pattern supporting enhanced showers statewide in a plume of 2"+
precipitatble water values ahead of an approaching trailing cold
front slated to reach the state later next week.

Schichtel