Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
708 AM EST Sat Nov 18 2017

Valid 00Z Sun Nov 19 2017 - 00Z Sun Nov 26 2017

Models agree in principle that mean troughing aloft over and
northeast of the state through the period will keep precipitable
water values well below climatological levels, with some modest
fluctuation in response to individual shortwaves within the mean
trough.  As a result expect windward-focused (but occasionally
straying to leeward locations) shower activity to be on the
lighter side of the spectrum.

The strongest feature to affect the islands' weather will be from
now into early next week, an upper trough and surface low to the
northeast of the area.  Guidance agrees that lowest heights aloft
will pass over the state around Sunday followed by northeastward
progression of the shortwave.  The associated cold front is
currently crossing the region and will remain to the east after
passage.  The flow between the surface low and central Pacific
high pressure will lead to brisk winds generally from the
northwest or north into the first part of next week.  Then from
midweek onward the surface high should extend far enough southeast
to return winds to a more typical northeasterly or easterly
orientation.  A fairly tight pressure gradient will likely keep
winds on the brisk/strong side into next weekend.  There is
reasonable model/ensemble agreement on the surface pattern through
Thursday-Saturday though low-predictability detail differences
aloft develop.  

Rausch