Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
328 PM EST Sat Feb 24 2018

Valid 12Z Wed Feb 28 2018 - 12Z Sun Mar 4 2018

...Guidance/Predictability Assessment and Weather
Highlights/Threats...

The beginning of the medium range period will feature a narrow
ridge axis extending from the north-central Pacific to western
Alaska, with upper level lows over eastern Russia and near British
Columbia.  This pattern is expected to change by the end of the
week and into next weekend as the ridge breaks down with the flow
becoming more zonal in nature.  Model differences increase quite a
bit beyond day 6 with a wide variety of ensemble member solutions
noted, decreasing confidence in the forecast for Friday and
beyond.  Therefore, significant changes with future forecast
updates are likely.   Accordingly, the WPC medium range product
suite was primarily derived from a blend of the GFS/ECMWF/CMC days
4-6 and then mostly ensemble means into days 7 and 8. 

Hamrick