Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
825 AM EDT Sun Apr 01 2018

Valid 00Z Mon Apr 02 2018 - 00Z Mon Apr 09 2018

...Excessive Rainfall Threat...

Models and ensembles agree that a closed low now northwest of the
state will continue to eject away from the state this weekend and
be replaced by additional dynamic systems midweek and next
weekend. Latest guidance forecast spread has improved with this
subsequent series of systems and this would seem to bolster
confidence in the evolution of the wet pattern underneath into the
islands. A favored model and ensemble composite spreads deepest
moisture from the western islands this weekend to the central and
southern islands mid to late week. Expect a trailing surface front
now stalled near Kauai will be periodically reinforced and forced
across the islands during the upcoming week as lows develop and
lift northeastward along the well defined boundary. Models and
ensembles along with latest blended TPW imagery still indicate
that an anomalous plume (200% of normal) with upwards of 2"
precipitatble water values will accompany the front. This deep
tropical moisture will be available to repeatedly fuel heavy
rain/convection along and ahead of the front to enhance a local
runoff threat.

Schichtel