Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
723 AM EST Tue Feb 27 2018

Valid 00Z Wed Feb 28 2018 - 00Z Wed Mar 7 2018

The models and ensembles are in decent agreement on the synoptic
scale pattern over the Hawaii domain through Friday night.  A hint
of a temporary omega block flow pattern over the central Pacific
is indicated in the guidance from late Wednesday through Friday,
with the main ridge axis situated generally near 150W with upper
level troughs to the southwest and southeast of the upper level
high.  Similar to yesterday, the EC mean remains slightly more
amplified with the upper level ridge than the GEFS mean, with both
solutions breaking down the ridge by next Sunday.  Another weak
upper low will likely form near 170W by Friday and into Saturday
according to both the GEFS and EC means.  This may once again
advect deeper moisture northward across the westernmost part of
the Islands for the end of the week. 

Differences in the guidance become apparent in the mid-latitude
flow north of the Islands beginning early Saturday with respect to
a potent storm system north of 40N.  The GEFS mean is more
suppressed with this feature and brings mid-level height falls and
a cold front closer to the state than the EC mean that is
indicating more of a mean level ridge.  Given the better
continuity with the EC mean, this model is currently preferred for
the end of the forecast period.

D. Hamrick