ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 139 PM EST WED FEB 25 2015 VALID 12Z SUN MAR 01 2015 - 12Z THU MAR 05 2015 THE ALASKA MEDIUM RANGE FORECAST CONTINUED TO RELY UPON A BLEND OF THE ECENS/NAEFS MEANS. FOR THE 25/00Z FORECAST CYCLE---THE 25/00Z ECENS/NAEFS MEANS SUPPORT A NORTHWARD SHIFT OF THE WINTER STORM TRACK--- AND INTO THE NORTHERN BERING SEA AND NORTHERN ALASKA. THE TRANSITION BEGINS IN THE DAY 4 TIME FRAME---WITH A LEAD UPPER-LEVEL TROUGH MIGRATING FROM WEST TO EAST ALONG THE ARCTIC CIRCLE FROM 140W INTO CENTRAL NORTH AMERICA. THE TRANSITION APPEARS TO BE COMPLETED IN THE DAY 7 TIME FRAME...AFTER A SECOND UPPER-TROUGH MIGRATES FROM THE DATELINE TO 140W AND DE-AMPLIFIES THE UPPER LEVEL FLOW AND SUPPRESSES THE QUASI-STATIONARY UPPER-LEVEL RIDGE AXIS ALONG 55N 140W. BETWEEN DAY 6 AND DAY 8...A FAST-ZONAL ALOFT IS EXPECTED TO PREVAIL---WITH LOW-AMPLITUDE WAVES TRANSITING THE INTERIOR AND GULF OF ALASKA. THIS LOW-AMPLITUDE WESTERLY FLOW ACROSS MOST OF THE STATE---BRINGS A TEMPORARY END TO THE HIGHLY-AMPLIFIED FLOW---THAT HAS PLAGUED THE GULF OF ALASKA FOR MANY WEEKS. OVERALL...THIS WILL BRING AN END TO MILDER AIR OVER THE STATE---WITH THE PERSISTENCE OF MIGRATORY UPPER-LEVEL TROUGHING---GRADUALLY MODIFYING THE WARMTH WITH A MIX OF MERGING CLOUD LAYERS AND PERIODS OF LIGHT PRECIPITATION. THIS FORECAST PERIOD... THE GEFS CONTINUES TO BE THE PROGRESSIVE SOLUTION FROM THE DATELINE EASTWARD BETWEEN 50N-60N---BOTH IN THE BERING SEA AND NORTH CENTRAL PACIFIC VERSUS THE ECENS MEANS. THOUGHT THE INCORPORATION OF THE NAEFS (AGAIN TODAY) REPRESENTS A GOOD MIDDLE GROUND FOR EMBEDDED MID-LEVEL ENERGY INJECTING INTO THE UPPER-LEVEL TROUGH---ALONG AND DOWNSTREAM OF 150W LONGITUDE AND IMPINGING UPON THE UPPER-LEVEL RIDGE AXIS. IF AND WHEN THE UPPER-LEVEL RIDGE 'RE-APPEARS' OR DISAPPEARS FROM THE EASTERN GULF AND PANHANDLE---REMAINS OUTSIDE OF THIS ALASKA MEDIUM RANGE FORECAST PACKAGE. VOJTESAK