Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
406 PM EDT Tue Aug 21 2018

Valid 12Z Sat Aug 25 2018 - 12Z Wed Aug 29 2018

...Guidance/Predictability Assessment and Weather Threats...

Models and ensembles indicate that a blocking high will become
anchored over the Northeast Pacific as a broad positively-tilted
trough with numerous mid-latitude disturbances are forecast to
converge over the Bering Sea during the medium range period.  The
ensemble mean solutions from the 00Z EC mean and 06Z GEFS appear
to offer to best starting point for handling this overall synoptic
pattern evolution through midweek next week.  The extratropical
remnants of Typhoon Cimaron from the western Pacific could move
into the picture by midweek as well.  It appears that the
Aleutians northeastward into western Alaska will be under an
active storm track into next week while southern and southeastern
Alaska will be under the protective influence of the blocking high
to the south.  The WPC Alaskan grids were derived from a consensus
of the 00Z EC mean and the 06Z GEFS mean mixing in with a higher
percentage of the 00Z ECMWF and the 12Z GFS for Days 4 and 5.

Kong


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