Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
240 PM EST Mon Feb 26 2018

Valid 12Z Fri Mar 2 2018 - 12Z Tue Mar 6 2018

The forecast period begins on Friday with an elongated upper ridge
axis extending from the Gulf of Alaska to north of the Arctic
Coast, and upper level troughs over the Bering Sea and the
Northwest Territories in Canada.  The models and ensembles are in
relatively good agreement with the overall pattern for the end of
the work week.  There are some differences with the low forming
over the northern Pacific south of the Aleutians, with the 12Z CMC
slower and the GFS tracks the low well to the south of the model
consensus and south of the GEFS mean.  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 upper level
ridging attempting to briefly build back in over Alaska on Sunday
followed by another storm system approaching from the Bering Sea
early next week.  The forecast for this time period was derived
mainly from the 00Z EC mean and some of the ECMWF and NAEFS mean,
since the GFS is indicating a greater degree of troughing over the
northern Pacific where the ensemble means are favoring more zonal
flow for next Monday.  This also maintains better continuity with
the previous forecast.

In terms of sensible weather impacts, the central and eastern
parts of the state should be dry and cold on 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 over the weekend for western Alaska and the
southern coast as a Bering Sea storm system approaches the region,
along with a slow moderation in temperatures going into early next
week.

Hamrick