Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
242 PM EST Sun Feb 25 2018

Valid 12Z Thu Mar 1 2018 - 12Z Mon Mar 5 2018

The forecast period begins on Thursday with an elongated upper
ridge axis extending from the central Pacific to north of the
Arctic Coast of Alaska, and upper level troughs over eastern
Russia and northwestern Canada.  The models and ensembles are in
relatively good agreement with this pattern for the end of the
work week, with the CMC being the most amplified with the ridge
axis compared to the model consensus.  The model solutions
indicate increasing spread next weekend as potent shortwave energy
embedded in the Bering Sea trough begins breaking down the ridge
over Alaska and de-amplifies the flow some, with the CMC ensemble
mean being the quickest to do this compared to the GEFS and EC
means.  There is also more spread noted in the CMC ensemble
members as well.  In terms of deterministic model solutions, the
past few runs of the GFS have indicated better run-to-run
consistency than the ECMWF, which had indicated much more in the
way of upper level ridging over northern Alaska compared to its
00Z run this morning.  There is also a good indication of a Bering
Sea low pressure system developing by the Sunday to Monday time
period, and another one around 45 degrees north that would be
south of the eastern Aleutians.

In terms of sensible weather impacts, the majority of the state
should be dry and cold on Thursday and Friday with an arctic
surface high governing the weather pattern, and a stationary front
near the southeast Panhandle region.  Precipitation chances are
expected to increase by Sunday for western Alaska as a Bering Sea
storm system approaches the region, along with a slow moderation
in temperatures.

Hamrick