Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
718 AM EST Fri Dec 26 2014

Valid 00Z Sat Dec 27 2014 - 00Z Sat Jan 03 2015

The 26/00Z ECENS/GEFS and their deterministic solutions were a tad
slower/faster respectively than their 25/00Z solutions---but
maintain a mid-level trough migration across Hawai'i between
31/00Z and 1/00Z. This is consistent with the 25/00Z cycle but the
deterministic 26/00Z GFS continues to be the faster solution in
the Subtropics and downstream across the east central Pacific and
US mainland---beyond day 5 (Wednesday).

The system---migrating across the Dateline on Sunday and reaching
155W next Wednesday---remains 'on track'---with the deterministic
ECMWF a more aggressive forecast approach versus the GFS---because
the GFS IS faster and weaker aloft.

At 500mb (between 1/00Z and 3/00Z), this translates to 10 degrees
of separation (longitude) along 40N latitude between the 26/00Z
GFS deterministic (150W) and the 26/00Z deterministic ECMWF
(160W). With this next west-to-east moving mid-level trough in the
pattern/sequence---the ECMWF again would be the aggressive
solution in the Subtropics and Hawai'i.

For the day 5-7...recommend a blend of the last 2 ECENS mass field
forecasts---the 25/12Z and 26/00Z cycles. Prior to day 5...the
26/00Z deterministic appeared to have utility in handling the
smaller-scale details and the regional sensible weather pattern in
and around Hawai'i.

Vojtesak