Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
351 AM EDT Mon Sep 11 2023

Valid 00Z Tue Sep 12 2023 - 00Z Tue Sep 19 2023

Latest guidance looks consistent and similar for the pattern
evolution into early next week.  Mid-latitude Pacific high
pressure will promote brisk trades during the first half of this
week while below-climatology precipitable water values should keep
mostly windward/mountain-focused rainfall on the light side. 
Trades will likely trend lighter after midweek, first due to a
cold front producing a break in surface ridging to the north
Thursday-Friday and then a remnant surface trough from former
tropical cyclone Jova moving through from east to west during the
weekend.  Models/means continue to show an upper ridge persisting
over the islands into Friday and then rapidly collapsing as
shortwave energy descends from the north.  This energy may also
contribute to the weaker surface pressure gradient.  The forecast
remains on track for the trades bringing in pockets of greater
moisture after midweek, some originating from Jova.  This moisture
will likely raise precipitable water values somewhat above normal
from around Friday onward, with lower heights aloft providing
another ingredient for increasing rainfall totals by the weekend.

Rausch