ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 235 PM EDT TUE MAR 18 2014 VALID 12Z SAT MAR 22 2014 - 12Z WED MAR 26 2014 RELIED ON THE MOST RECENT EUROPEAN CENTRE ENSEMBLE MEAN AS A SYNOPTIC GUIDE FOR THE ALASKA REGION AT THE MEDIUM RANGE. THE EUROPEAN CENTRE GUIDANCE--INCLUDING THE ECMWF RUNS--HAVE BEEN THE MOST CONSISTENT AND SKILLFUL IN DEPICTING THE UPCOMING BLOCKING PATTERN. BY THE WEEKEND, THE UNDULATING FLOW ASTRIDE THE ALASKAN ARC OF THE ARCTIC CIRCLE SHOULD BUCKLE INTO A HIGH-OVER-LOW BLOCK, WITH THE HIGH PORTION ANCHORING JUST OFF THE NORTHERN SHORE. SPRAWLING CYCLONES EMERGING FROM KAMCHATKA WILL BE FORCED SOUTH OF THE HIGH JUST BEYOND THE WATERS OF THE GULF-PROPER, SHEARING EASTWARD TOWARD THE PANHANDLE AND WEST COAST OF CANADA. POPS WILL BE HIGHEST EARLY IN THE PERIOD OVER THE SOUTHERN PANHANDLE AND ALEUTIANS, WITH A GRADUAL DWINDLING OF MOISTURE AS THE BLOCK TIGHTENS AND SQUEEZES OFF FRESH ADVECTIONS FROM LOWER LATITUDES. THE NORTH-SLOPE 12-HOUR POPS REMAIN BELOW 5-PERCENT THROUGH THE ENTIRE FORECAST. THE INTERIOR AND PANHANDLE WILL BE COLDER THAN OF LATE ON THE WESTERN SIDE OF THE BIG ARCTIC HIGHS DISLODGING DOWN THE HIGH PRAIRIES OF CANADA. CISCO