Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
347 AM EDT Tue Jul 04 2023

Valid 00Z Wed Jul 05 2023 - 00Z Wed Jul 12 2023

Today's guidance shows good agreement and continuity with the
forecast through about Saturday, and then some detail
differences/trends by Sunday-Tuesday.  The most persistent theme
is for moderate to brisk trades and windward/mountain focus for
most showers through the period.  Eastern Pacific high pressure
will weaken a bit as it drifts southwestward closer to the state,
with consensus still showing a net effect of strengthening the
trades by the weekend.  Guidance is consistent in merging this
high with another one approaching from the west during the weekend
but latest trends show greater strength of the western high by
early next week.  This high should keep trades on the brisk side
at that time.  Expect most rainfall in showers to be fairly light
through Saturday with a combination of below-climatology
precipitable water values and the islands being under the northern
periphery of an upper ridge to the south.  Rainfall totals may
increase some during Sunday-Tuesday.  Guidance consensus shows the
upper ridge giving way to a broad area of lower heights with one
or more embedded weak lows heading into the region from the
northeast, while a pocket of moisture associated with former
Hurricane Adrian may pass through at least parts of the state. 
There has been some divergence over the past day on the timing and
track of this area of moisture, with 00Z GFS/GEFS mean runs
farther south than yesterday's continuity but similarly timed
while the 00Z ECMWF and 12Z ECMWF mean are farther north and
slower.  A compromise approach would provide the best continuity
while awaiting a return to better guidance agreement.

Rausch