Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
259 AM EST Tue Nov 29 2022

Valid 00Z Wed Nov 30 2022 - 00Z Wed Dec 07 2022

The areas of heavy rainfall associated with abundant tropical
moisture and shortwave energy early this week should taper off
after Tuesday as upper heights rise somewhat.  There is still a
reasonable consensus that high pressure to the distant northeast
of the state will promote a return to more typical light/moderate
trades and windward shower focus late this week into the weekend. 
However, guidance has been struggling to determine the finer
details of upper ridging that sharpens near 160W longitude around
Wednesday-Thursday and gradually weakens/drifts eastward
thereafter, along with how far south/southwest into the region
drier air to the north reaches.  After the widely-varying guidance
had clustered 24 hours ago toward more moisture staying over the
state after midweek, the models/means now cluster just as well
toward a pronounced drying trend with precipitable water values
declining to near average for a time around the late week/early
weekend time frame.  Moisture may rebound somewhat and the trades
weaken as a front approaches from the west late weekend into early
next week.  Again by early next week there are some significant
differences for how sharpening shortwave energy to the northwest
evolves, leading to issues with the surface forecast.  The 00Z
ECMWF is most at odds with most other models/means, closing an
upper low just west of 170W by next Tuesday.  The associated
surface reflection leads to strengthening southeasterly winds over
the state.  Remaining guidance still differs at the surface and
aloft but overall suggests maintaining some degree of more typical
trade flow, though possibly hindered by surface troughing for a
time.

Rausch