Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
254 PM EST Sun Jan 6 2019

Valid 12Z Thu Jan 10 2019 - 12Z Mon Jan 14 2019

The model ensemble means and the deterministic GFS/ECMWF/CMC are
in relatively good agreement on the synoptic scale for the
beginning of the forecast period, with more model spread noted
across the northeast Pacific.  The active storm track remains
south of mainland Alaska, with a major oceanic storm developing
Wednesday night south of the Aleutians with central pressure
likely below 960 mb.  Deterministic model spread differs
significantly by Saturday regarding the development of a triple
point low near 50 degrees north, along with multiple perturbations
pivoting around the main storm center.  By the end of the forecast
period next Monday, overall forecast is low over the north Pacific
and near average over mainland Alaska.  Given that the ECMWF/EC
mean has handled the synoptic pattern the best for areas south of
Alaska over the past couple of days, we will continue to lean
toward these solutions.  Therefore, the latest WPC Alaskan grids
were based on a weighted consensus from these model solutions: 00Z
EC mean, 00Z ECMWF, and 6Z GFS with a preference to the ECMWF/EC
mean.  Some CMC was also used through Friday before model
solutions diverged further.

In terms of sensible weather, frigid temperatures will be the main
story making headlines across much of the Interior and extending
to the Arctic Coast at the beginning of the forecast period
Thursday, with some overnight lows in the minus 40s likely for
some of the sheltered valleys!  A gradual moderating trend is
expected to ensue by next weekend, but slower than previously
advertised owing to a blocking flow pattern aloft and the slow
moving upper low over northern Alaska.  Strong winds are expected
for the Aleutians and the Bering Sea for the end of the week as an
intense oceanic storm approaches the central Aleutians and then
gradually weakens over the weekend.  Much of the mainland should
remain mostly dry with some scattered flurries, and rain/snow for
the southeast panhandle region and coastal areas of southern
Alaska and the Aleutians.

Hamrick


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