Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
825 AM EDT Thu Sep 5 2019

Valid 00Z Fri Sep 6 2019 - 00Z Fri Sep 13 2019

The GEFS and EC ensemble means are in good agreement on the
synoptic scale pattern across the central Pacific through Monday,
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 Depression 12E is expected to pass south of the state on
Sunday and Monday, with perhaps some heavier showers possible
across the Big Island. 

By Tuesday, the models begin to diverge on the expected evolution
of a trough across the northern Pacific that is currently over
Asia, with the EC faster and less amplified than the GEFS mean. 
This has implications on the upper level ridge to the south of the
trough, with the EC mean stronger and farther west with the
subtropical ridge by midweek.  By the end of the forecast period
next Thursday, there will likely be a col within the subtropical
ridge to the east of Hawaii, where the remnants of Hurricane
Juliette will likely reside.

Hamrick