ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 152 PM EST THU DEC 25 2014 VALID 12Z MON DEC 29 2014 - 12Z FRI JAN 02 2015 ACTIVE TROUGH IS ANTICIPATED IN THE WESTERN BERING SEA AND ALEUTIANS THIS ALASKA MEDIUM RANGE. A RELEASE OF ARCTIC AIR INTO THE LOWER 48 SPREADS WESTWARD ACROSS THE PANHANDLE AND INTO THE FAR EASTERN/NORTHEASTERN GULF OF ALASKA AND HIGH PRESSURE PREVAILS ALONG 120W-130W FROM THE ARCTIC CIRCLE SOUTHWARD INTO THE PACIFIC NORTHWEST STATES---WASHINGTON/OREGON. THE 25/00Z ECENS MEAN AND 25/006Z GEFS MEAN DO A GOOD JOB OF REPRESENTING THESE TWO SYNOPTIC-SCALE FEATURES THROUGH THE ALASKA MEDIUM RANGE PERIOD...AND FOR SOME OF THE SURFACE GRAPHIC DETAILS---WPC UTILIZED THE 25/00Z DETERMINISTIC TO HANDLE THE SUBTLE PROGRESSION OF THE LOW-LEVEL FLOW AND WEAK SURFACE STATIONARY FRONT DEVELOPING OVER THE GULF OF ALASKA---THE RESULT OF COLD CANADIAN AIR SPILLING ACROSS THE PANHANDLE AND 'DEPOSITING' IN THE EASTERN GULF OF ALASKA. THE SUBTLE 'KEY' IN THE MEDIUM RANGE PATTERN---IS THE NORTHEASTWARD PROGRESSION OF THE UPPER-LEVEL TROUGH AND ITS 'ABILITY' TO EJECT MID-LEVEL ENERGY---SOUTHEASTWARD---ACROSS THE SOUTHEAST BERING...EASTERNMOST ALEUTIANS AND INTO THE NORTHWEST GULF OF ALASKA. VOJTESAK