Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
347 AM EDT Sun Sep 25 2022

Valid 00Z Mon Sep 26 2022 - 00Z Mon Oct 03 2022

Guidance again shows fairly good agreement and continuity for the
general pattern.  Recent light southeasterly winds should be
turning more easterly for late this weekend into the first half of
the work week as surface ridging north of the state takes on an
east-west orientation.  Trades will still be on the lighter side
though, with a front settling to a position near or just north of
25N latitude.  Thus showers may exhibit a combination of
windward/mountain focus and sea breeze influence depending on
location.  Expect somewhat stronger trades after midweek and
continuing through the weekend as the front weakens and a couple
separate surface highs exert some influence.     

As for moisture, consensus shows a decent gradient in precipitable
water values setting up through Thursday.  Southeastern islands
should see below normal values while northwestern islands will
likely be above normal, in the southern periphery of the moisture
band associated with the stalled front.  Around Friday the
GFS/ECMWF carry a band of enhanced moisture embedded within the
trades across the area, with the ensemble means offering a more
subtle depiction of this idea.  The 00Z ECMWF and 00Z GEFS/12Z
ECMWF means then show a return to drier conditions for the weekend
but the 00Z GFS brings in another band of moisture from the east
on Sunday.  Given the low predictability of such pockets of
moisture that far in advance, the drier consensus seems better for
now.  Expect the majority of rainfall through the period to be
fairly light.  Some localized enhancement would be possible with
individual moisture bands such the one that may pass through
Friday, and any upper impulses that may reach the area within an
area of gradually declining upper heights next weekend.  

Rausch