Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
715 AM EST Sat Feb 20 2016

Valid 00Z Sun Feb 21 2016 - 00Z Sun Feb 28 2016

The 20/00Z GEFS/ECENS means and their deterministic runs continue
to be very reasonable solutions through Thursday (day 5).
Deepening surface cyclone invof 36N 150W will track northeastward
--- but will spread a well-defined mid-latitude cold front
southward that migrates across the western portion of the state
early Monday and reaches the Big Island by Monday evening. A drier
airmass should build in temporarily behind this frontal passage on
Tuesday. 

Going forward into the Thursday time frame (around 25/12Z) --- the
deterministic 20/00Z ECMWF --- like its 19/00Z predecessor ----
maintains a slightly weaker mid-level trough and frontal structure
versus the 20/00Z GFS invof 30N 155W. This frontal passage could
be easily handled by using a blend of both deterministic solutions
--- even at day 5. What deterministic differences do occur --- are
downstream of Hawai'i and do not appear to alter the flow pattern
--- heading into day 6/7 time frame.

Given the mid-latitude north central Pacific Ocean (between
150W-160W) remains an active region of cyclogenesis during the
latter half of this particular forecast period --- suggest using a
2/3rds GEFS-1/3rd ECENS blend for day 6 and day 7 --- to mitigate
some of the 'deterministic' shortwave details south of the
Aleutians (invof 50N 160W).

Vojtesak