Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
717 AM EST Tue Dec 29 2015

Valid 00Z Wed Dec 30 2015 - 00Z Wed Jan 06 2016

At the onset of the period, amplified flow is confined to
locations north of the 30 degree north latitude line. A weak
shortwave trough is seen exiting eastward away from the island
chain as heights begin to build in its wake. Otherwise, the upper
pattern is rather quiet as the primary core of height falls
remains well to the north of Hawai`i.

Looking at the surface, a cold front shearing in the vicinity of
the northern most islands will lead to a distinct wind shift
bringing about northerly flow for Wednesday morning. This will
quickly give way to easterly trades through Thursday. Eventually a
surface high building northwest of Hawai`i should lead to enhanced
northeasterlies on Friday evening into Saturday morning. Some
guidance shows near 20-25 knots of sustained flow at this time. An
additional return of this enhanced low-level flow may occur early
next week given another surface ridge building to the north.

Regarding precipitation, the moisture generally gets scoured out
as the cold front sweeps southward during the next couple of days.
This generally lowers precipitable water values to the 0.50-0.75
range for the remainder of the period. Precipitation chances are
rather low except for terrain-driven showers and anything that can
develop along local sea breezes.


Rubin-Oster