Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
304 PM EST Sun Jan 20 2019

Valid 12Z Thu Jan 24 2019 - 12Z Mon Jan 28 2019

Upper levels remain mostly well-forecast with a longwave
trough/ridge pattern slowly translates westward into next weekend.
Successive central Pacific systems will help to tug the trough
axis from the central/western Bering toward Kamchatka as the ridge
pokes northwestward across the North Slope. The models/ensembles
have struggled with how lead systems moving out of the central
North Pacific Wed/Thu weaken into Southcentral and also across the
Gulf of Alaska into the Panhandle. Preferred a consensus solution
despite the differences given the uncertainty with among the
recent GFS runs and the ECMWF and GEFS/ECMWF ens means to prevent
too much day to day shifting. For late week through the weekend,
agreement was comparatively better given the lead time which
should take a respectably deep system (960s mb or lower) across
the western Aleutians into the Bering Sea before being blocked by
the ridging to the east.

Temperatures will moderate with sustained southerly flow aloft
that should work its way to the surface. Precipitation (snow but
coastal rain) will focus from Kodiak/Southcentral into the
Panhandle Thu-Sat but then back to the Aleutians as the deeper low
approaches.

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