Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
811 AM EDT Wed Apr 08 2015

Valid 00Z Thu Apr 09 2015 - 00Z Thu Apr 16 2015

The 8/00Z GEFS, ECENS, NAEFS ensemble means and their
deterministic runs maintain a rather persistent flow pattern for
the Subtropics and Hawai'i this forecast period---with mid-level
and upper-level westerlies prevailing at low latitudes. The
persistent westerlies offer little amplitude across the central
Pacific through the weekend (day 3-4 period)---but induce plenty
of shear---upon a cutoff low currently near 29N179W---streaming
mid-level moisture eastward across the Hawai'i forecast area.

Around day 5 (next Monday), these low-latitude westerlies begin to
shift northward---in response to an amplifying trough invof the
central Aleutians near 170W. This trough migrates eastward to 160W
longitude by Tuesday and 150W longitude by next Wednesday (day 7).
Embedded within this trough axis---a surface cyclone---which will
draw a cooler airmass southward towards 30N latitude.

This front appeared to be the only synoptic-scale feature of
note---during the latter half of the forecast period---with the
deterministic GFS/ECMWF offering slightly different storm tracks
across the mid-latitude Pacific. For now, recommend a blend of the
8/00Z ECENS and NAEFS beyond day 5.

Vojtesak