Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
715 AM EST Mon Dec 24 2018

Valid 00Z Tue Dec 25 2018 - 00Z Tue Jan 01 2019

...Heavy Rainfall Potential...

Trades slacken over the next few days as trough passage to the
north interacts with a retrograding upper level low that works
underneath over the state. In this pattern a front weakens
northwest of the islands and lead showers become increasing fueled
by deepening moisture. This developing wet pattern will be further
enhanced Friday through the weekend a moisture pooling front works
across the islands from the northwest coincident with
amplification and approach of a mid-upper level trough/potential
closed low. The 06 UTC GFS and 00 UTC ECMWF are less amplified
with the feature than the 00 UTC UKMET/Canadian, but upstream
mid-upper level ridge amplitude may favor amplitude. Accordingly,
there is a threat for heavy rainfall and runoff problems.

Schichtel