Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
802 AM EDT Sun Apr 24 2016

Valid 00Z Mon Apr 25 2016 - 00Z Mon May 02 2016

Recent guidance is fully-supportive of the local Hawai'i forecast
scenario through day 7.

From a large-scale perspective --- the mid-latitude Pacific is in
a rather stable forecast pattern --- and not much difference
between the ECENS-GEFS and NAEFS means. The 24/00Z ECMWF/GFS
deterministic runs suggest another deep cyclone eventually
develops in the northeast Pacific --- but differ in timing (the
ECMWF a day earlier day 6) versus the GFS. This feature should
emerge and begin to dominate the northeast Pacific --- but its
details (a stable lat/long location) --- going forward --- will
generate adjustment.

In either case though --- the weak surface trough expected to
migrate along 30N and briefly 'weaken' the broad Subtropical Ridge
on/around day 5 --- passes to the north of the Hawai'ian Islands
without much fanfare.

And a blend of the three means thereafter --- should lock down a
slowly-building and amplifying mid-level ridge in the central
Pacific Basin. The question will be --- in the day8+ / day11+ ---
time frame. And related to the longitude where the ridge axis
amplifies and settles in --- longer term.

Vojtesak