Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
816 AM EDT Wed Oct 08 2014

Valid 00Z Thu Oct 09 2014 - 00Z Thu Oct 16 2014

The ECENS/GEFS from 8/00Z were in adjustment 'mode' for a brief
time period along the western coast of North America between
12/12Z and 14/00Z, and primarily at mid latitudes. The entrainment
of western Pacific tropical moisture and dynamics from a distant
'Vongfong" seem to have been resolved and do not impact the medium
range forecast period invof the Dateline and Aleutians.

The 8/00Z ECENS/GEFS maintain the presence of a closed mid-level
disturbance migrating southwestward---from the east central
Pacific towards Hawai'i. Likewise, the 8/00Z deterministic
guidance (ECMWF-GFS-Canadian) are showing consistency with the
500mb vorticity between 13/00Z and 14/12Z invof the forecast area
to warrant---some sensible weather change to accompany the
circulation. The 8/00Z GFS is deeper than its ensemble mean while
the 8/00Z Canadian run is faster with the westward progression of
the feature versus the 8/00Z GFS-ECMWF deterministic runs and both
8/00Z GEFS-ECENS solutions.

A blend of the 8/00Z ECENS and GEFS would cover the mass field
forecasts for depth and forward (westward) motion of this
mid-level feature. 

Overall, the ECENS ensemble members are favoring more amplitude
with the north Pacific flow pattern and downstream across the
Mainland---and the 8/00Z GEFS is adjusting to this---in comparison
to its 7/00Z GEFS solution. The GEFS continues to favor a much
flatter flow over the northeast pacific between 12/12Z-14/00Z
versus the ECENS, so the pattern transition and details will be in
flux for a 1-2 day period. What the 8/00Z GEFS does do---that the
deterministic 8/00Z GFS-ECMWF and Canadian runs are suggesting
is---more amplitude will develop over the Gulf of Alaska and
eastern Pacific along 135W (southward into the Subtropics). This
amplification in turn, will slow down the disturbance passing near
the Islands between Monday and Wednesday.

Vojtesak