Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
712 AM EST Sun Nov 27 2016

Valid 00Z Mon Nov 28 2016 - 00Z Mon Dec 05 2016

One surface high to the northeast of the state followed by another
high progressing along 35-40N latitude will support fairly brisk
trades through mid-late week.  Lightest shower activity should be
at the start of the week when precipitable water values are
lowest.  PWATs increase somewhat by Tuesday-Wednesday as GFS/ECMWF
runs both bring in a pocket of moisture from the northeast.

From later in the week through next weekend guidance continues to
anticipate a wetter pattern.  Based on the full array of guidance
there is average or better confidence in the overall evolution
aloft but continuing spread that tempers confidence in extent of
greatest moisture/rainfall over the islands.  Sheared shortwave
energy approaching the islands from the northwest Tuesday will
evolve into an upper low to the south or southeast of the islands
by Thursday-Friday.  Exact position of this low will be crucial in
determining how far northwestward lower latitude moisture will be
drawn into the region.  Then amplifying upstream energy will
dislodge the upper low but likely pull more moisture northward
next weekend and possibly beyond.  Spread is not quite as great as
24 hours ago but guidance maintains the same relative positions
for both the upper low and upstream amplification.  Prefer a
solution that is halfway between the ECMWF/ECMWF mean which
position both features farther westward, and would bring more
moisture across the state, than the GFS/GEFS solutions.  The 00z
CMC is even farther westward than the ECMWF with the upstream
amplification but otherwise the CMC/CMC mean are closer to the
GFS/GEFS than yesterday so an even compromise appears best at this
time.  Corresponding to the evolution aloft expect some degree of
inverted surface troughing to develop with a lighter trend/altered
orientation for trade flow.

Rausch