Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
825 AM EDT Fri Sep 6 2019

Valid 00Z Sat Sep 7 2019 - 00Z Sat Sep 14 2019

The GEFS and EC ensemble means are in good agreement on the
synoptic scale pattern across the central Pacific through early
next week, with an upper level ridge becoming established north of
Hawaii near 35 degrees north and a large surface high near 40
degrees north.  This would result in breezy east to northeast
trade winds across the Islands and enhanced showers across the
favored windward terrain.  An enhanced plume of moisture
associated with Tropical Storm Akoni is expected to pass south of
the state on Sunday and Monday, with perhaps some heavier showers
possible across the Big Island. 

By Tuesday and beyond, the GEFS mean and EC mean have come into
better agreement on the expected evolution of a trough across the
northern Pacific that is currently over Asia, with the EC now just
slightly faster and less amplified than the GEFS mean.  By the end
of the forecast period next Friday, there will likely be a col
within the subtropical ridge near 140 degrees west, with a hint of
a weak upper low suggested by the latest GFS and ECMWF.

Hamrick