Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
202 PM EST Mon Jan 21 2019

Valid 12Z Fri Jan 25 2019 - 12Z Tue Jan 29 2019

Longwave pattern will slowly translate the trough/ridge couplet
westward this weekend as shortwaves eject northeastward out of the
northern Pacific farther to the west. System
timing/track/intensity specifics remain tough to pinpoint given
the multitude of smaller scale shortwaves and the deterministic
models remain quite varied from run to run. Thus, opted to again
remain near a consensus between the 00Z GEFS and ECMWF ensemble
means through the period but with more emphasis on the ECMWF
ensemble mean by next week (Mon-Tue) as it was farther west with
the trough which has been the trend. Was able to add the 12Z
GFS/00Z ECMWF for some detail earlier in the period but that still
resulted in changes in mostly the speed of the lead systems.
Ensemble spread increased only nominally with lead time so the
deeper Bering system actually showed fewer changes than the
systems on Fri/D4-Sat/D5.

Temperatures will moderate over the state to above average with
ridging across the interior. Precipitation (snow but coastal rain)
will focus initially from Kodiak/Southcentral into the Panhandle
Fri-Sat but then mostly across the Aleutians into southwestern
Alaska as the deeper low moves through the Bering Sea.

Fracasso


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