Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
342 AM EDT Sat Jul 16 2022

Valid 00Z Sun Jul 17 2022 - 00Z Sun Jul 24 2022

...Winds and tropical moisture from Darby likely to affect parts
of the state this weekend...

Guidance continues to agree well for the general forecast through
the period, and in fact now clusters somewhat better than
yesterday for some details late next week.  High pressure well
north of the state will maintain moderate to brisk trades through
next week, supporting a windward/mountain focus for rainfall.  The
0300 UTC Central Pacific Hurricane Center advisory shows Tropical
Storm Darby steadily weakening toward depression status as it
passes to the south of the Big Island today (Saturday).  Darby's
passage will lead to a brief period of stronger winds along with
enhanced and more widespread rainfall, mainly over and near the
Big Island.  Drier air will quickly move in from the east,
beginning what looks to be a lengthy stretch of below-climatology
precipitable water values with some day-to-day fluctuations. 
Therefore most showers should be fairly light after Darby's
passage.  Today's models/means are somewhat closer together for
the upper weakness advertised to extend into the area from the
northeast by mid-late week.  In particular the ECMWF has adjusted
eastward to the guidance average, so its moisture remains lower
like the GFS and ensemble means.  The 12Z ECMWF mean is still a
little west of consensus for the upper feature but not to the
extent of affecting the moisture forecast.

Rausch