Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
727 AM EST Tue Nov 12 2019

Valid 00Z Wed Nov 13 2019 - 00Z Wed Nov 20 2019

...Weekend Heavy Rain Threat...

Models and ensembles agree in showing a relatively benign weather
pattern for Hawaii into Friday in a pattern with weak flow and
limited moisture and showers. The pattern amplfies and becomes
more active over the weekend into early next week as guidance
shows an increasing signal for significant upper trough
amplification to the northwest of the state. Lowering heights and
increasing instability will accompany the approach of a cold front
into the islands along with a lead increase in deep layered
tropical moisture influx into the state. Solutions also agree on
the potential for moisture from an easterly wave to potentially
also be drawn northward into the frontal zone, with precipitable
water values rising upwards to 2 inches. This setup should support
the potential for an increasingly widespread threat of heavy
rainfall that could be prolonged by possible upper closed low
development and the resumption of trades in a tightening pressure
gradient over the state as surface high pressure builds/bridges to
the north of the state. A composite guidance solution is favored
given favorable solution evolution/clustering.

Schichtel/Tate