Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
729 AM EST Tue Nov 17 2015

Valid 00Z Wed Nov 18 2015 - 00Z Wed Nov 25 2015

To begin the period, amplified flow in the mid-latitudes will
feature a closed low across 40N/165W. While a core of the height
falls continue migrating downstream, additional shortwave energy
is forecast to peel off and evolve into another closed low north
of the island chain by late in the work week. Thereafter,
deterministic solutions vary considerably but the ensembles
support the general notion that the flow will flatten out as the
greater amplification resides well to the north.

At the surface, the guidance shows a baroclinic zone approaching
Kauai but gradually weakening and evolving into more of a
north-south oriented inverted trough. The precipitation with this
feature should remain off toward the north although the persistent
trade winds are expected to foster shower development each day
across the Hawai`ian islands. This should be particularly the case
toward the Thursday/Friday time frame as 2 inch precipitable water
values approach the region. A gradual slackening in the prevailing
trades is forecast for the Sunday through Tuesday period in
response to the flattening mid-level flow field. Overall, would
begin leaning away from the deterministic guidance by Friday given
the differences in handling the closed low setting up north of
Hawai`i. Thereafter, a balance of the 06Z GEFS/00Z ECMWF ensemble
means will recommended.


Rubin-Oster