Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
340 PM EDT Fri Jun 01 2018

Valid 12Z Tue Jun 05 2018 - 12Z Sat Jun 09 2018

...Guidance/Predictability Assessment...

The WPC Alaskan medium range product suite was primarily derived
from a blend of the 00 UTC GFS/ECMWF and 00 UTC GEFS/ECMWF
ensemble means. Weighting was set as equal day4/Tuesday and then
gradually increased ensemble weighting days 5-8 consistent with
growing forecast spread. These 00 UTC guidance pieces cluster
better and maintain better WPC continuity than using of the newer
06/12 UTC versions of the GFS/GEFS mean in an overall pattern with
near normal predictability.

...Weather Highlights/Threats...

A main threat will be associated with heavy seas/precipitation and
winds wrapping around a deepened low and low re-developments as
potent energies cut underneath higher latitude mid-upper level
mean ridging on a general track from the southern Bering Sea
through the Aleutians/AKPen/SW AK into the Gulf of Alaska over the
course of next week. Activity will also work inland into southern
and southeastern AK as enhanced over windward terrain, but will
offer limited potential into the interior.

WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can be found at:

http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html