Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
816 AM EDT Fri Jun 09 2017

Valid 00Z Sat Jun 10 2017 - 00Z Sat Jun 17 2017

Mean mid/upper ridging initially over the Hawai`ian island chain
will gradually slide eastward toward the Eastern Pacific. Farther
upstream, amplified flow will stay well to the north across the
mid-latitudes although there are hints at a closed low forming
along the southern extent of these height falls. By Tuesday
morning, such a system begins to show up in the guidance,
particularly the 00Z ECMWF/ECMWF ensemble mean solutions. Some
form of weakness continues throughout much of the period although
its signal does diminish a bit in time.

At the surface, a climatological trade wind regime will dominate
with an increase in the low-level flow by early next week as a
surface ridge to northeast strengthens. The 06Z GFS/00Z ECMWF are
a tad stronger, possibly up to 20 knots on Monday. While a subtle
weakening is likely next week, expect persistent trades to
dominate during the foreseeable future. Regarding precipitation,
all solutions favor the usual trade wind driven showers with
heavier pockets along regions of upslope and in the vicinity of
mesoscale boundaries. The 06Z GFS/00Z UKMET are somewhat heavier
at times which makes some sense as precipitable water values
across the region rise above 1.50 inches. This is especially the
case over Kauai based on the latest model output from the GFS.


Rubin-Oster