Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
328 PM EST Tue Feb 27 2018

Valid 12Z Sat Mar 3 2018 - 12Z Wed Mar 7 2018

The forecast period begins on Saturday with an upper level ridge
breaking down over the Alaska mainland, and strong low pressure
systems over eastern Russia and south of the eastern Aleutians. 
The models and ensembles are in relatively good agreement with the
overall pattern for the weekend before greater large-scale
synoptic differences begin emerging for the beginning of next
week.  The greatest differences early in the period are in regards
to the low near 50N, with the ECMWF and its mean tracking it
farther to the north, and the GFS and its mean to the south and
west.  The model solutions indicate increasing spread by Sunday
night in regards to the Bering Sea trough and its embedded
shortwave energy, with the GFS among the fastest solutions and
forms a stronger system over the southern Alaska coast, whereas
the ECMWF is indicating an upper level trough.  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 early next week.  This also
maintains better continuity with the previous forecast.

In terms of sensible weather impacts, there should be a general
northwest to southeast temperature gradient, with the coldest
readings expected over the northeast quadrant of the state, and
moderating temperatures going through the weekend.  Precipitation
chances increase for the southern third of the state for the
weekend, and then the western part of the state early next week as
another storm system approaches from the Bering Sea.

Hamrick