Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
828 AM EDT Thu Jun 15 2017

Valid 00Z Fri Jun 16 2017 - 00Z Fri Jun 23 2017

The latest operational models and ensembles indicate a weakness in
the subtropical ridge over Hawaii at the beginning of the forecast
period.  The 00Z CMC differs the most from the consensus by
lingering this break in the ridge longer, and it is also slower
with the westward progression of a weak upper low east of the
islands early next week.  Both the GEFS mean and EC mean are in
good agreement in showing a gradual weakening of trades through
the middle of the weekend as a mid-latitude front reduces the
amount of surface ridging centered around 30 degrees north, and
then the surface high builds to the northeast of the state by the
end of the forecast period with the trades gradually increasing
again.

After today, expect rainfall activity to trend lighter as drier
air and upper level ridging gradually move in from the east. 
Given the slight reduction in the trades, there could be some sea
breeze influence for shower activity during the Friday to Sunday
time frame.  By next week, shower activity should once again
become terrain favored as the easterly trades increase.

Hamrick