Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
726 AM EST Fri Nov 20 2015

Valid 00Z Sat Nov 21 2015 - 00Z Sat Nov 28 2015

A favored composite of reasonably compatable larger scale model
and ensemble guidance inicates that a series of uncertain impulses
are feeding into a mean mid-level trough that will linger and be
periodically reinforced to the west-northwest and north of the
Hawaiian Islands. This will force an inverted surface trough
response over the next few days and a gradual frontal push into
the state early-mid next week. Pre-frontal winds will gain a
southeasterly then southerly component and this will continue to
support elevated precipitable water values pooling to around
1.50-2.00 inches or about +1.5 to +3.0 sigma. This would fuel some
heavier to locally excessive pre-frontal and frontal rains, as
enhanced by terrain lift. This is a wet pattern and a flash flood
watch has already been issued by the NWS forecast office in
Honolulu for the state. Trades and less unsettled weather is
expected to return to much of the state later next week as
post-frontal high pressure returns to the north of the state, but
lingering energy aloft and leftover boundary convergence could
still favor some showers.

Schichtel