Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
720 AM EST Sun Nov 20 2016

Valid 00Z Mon Nov 21 2016 - 00Z Mon Nov 28 2016

North of the Hawai`ian island chain, the pattern will remain quite
active across the mid-latitudes as a series of systems churn
eastward across the Central Pacific. Models do indicate a system
may close off west of the islands toward the International
Dateline. Unlike yesterday, most guidance now show this feature
although it does remain well to the west and generally out of the
picture. Looking to the middle to latter part of next week,
mid-level heights begin to build with a 588-dm ridge anchoring the
region. By next weekend, recent runs of the GFS/ECMWF and their
respective ensemble means do show a closed low pinching off east
of Hawai`i, generally in the vicinity of 140W longitude.

At the surface, a dome of high pressure to the north will continue
to favor an active period of trades. With a stronger ridge moving
through the early to middle part of next week, a strengthening of
the trades is likely as low-level winds may increase to 30 knots
or so. The persistence of this regime should continue throughout
the week given the surface high becomes a semi-permanent feature
to the northeast of the islands. Regarding precipitation, the
usual windward showers are possible throughout the period. Models
are rather light with forecast amounts given the best moisture
available appears to be displaced southward, particularly late in
the period.


Rubin-Oster