Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
823 AM EDT Sun Sep 17 2017

Valid 00Z Mon Sep 18 2017 - 00Z Mon Sep 25 2017

Ensembles remain in good agreement on the large scale flow over
the central Pacific over the next seven days. Strong upper/sfc
high to the north of the region will slide eastward and weaken
which will allow a weakness aloft to move westward and then
northwestward around the high's circulation to the northeast of
the area. Trades will be higher than average for most of the week
due to the strong pressure gradient but relax by the weekend as
the 1031-33 mb sfc high moves east of 150W by the weekend. The
island chain should remain in between the axis of moisture to the
northwest of the area and the ITCZ, but the ensembles show the
possibility of increased moisture to at least the Big Island
mid/late week. Generally, windward/mauka showers are expected
(though some leeward as well given breezy trades) with generally
light accumulations but some higher amounts may be possible on the
Big Island.


Fracasso