ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 258 PM EDT THU JUN 19 2014 VALID 12Z MON JUN 23 2014 - 12Z FRI JUN 27 2014 THE ALASKAN MEDIUM RANGE FORECAST CONTINUES TO BE DRIVEN BY SEVERAL APPROACHING/DEPARTING SYSTEMS AND DOWNSTREAM 'BLOCKINESS' AND RIDGING OVER NORTHWEST CANADA AND THE CANADIAN ROCKIES. MEDIUM RANGE GUIDANCE DEPICT A BROAD UPPER-LEVEL LOW MEANDERING OVER THE GULF OF ALASKA FOR THE NEXT WEEK WITH BETTER KICKER LOW/TROUGH ENERGY NOT TRACKING JUST TO THE SOUTH OF THE ALEUTIANS UNTIL LATE PERIOD. A SERIES OF WESTWARD-MIGRATING MID-LEVEL WAVES FORM ALONG THE NRN PERIPHERY OF THE BROAD CIRCULATION...BUT THE DETAILS OF INDIVIDUAL WAVE STRENGTH AND MIGRATORY TRACK HAVE BEEN LESS STELLAR. UP NORTH...EARLY NEXT WEEK CLOSED LOW/TROUGH ENERGY WILL BE KICKED MORE EFFICENTLY BY MID-UPPER LEVEL ARCTIC STREAM TROUGHING APPROACHING FROM THE NW OF THE STATE...LEAVING LESS ACTIVE ALASKAN FLOW INLAND. OVERALL...WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH ASSOCIATED SENSIBLE WEATHER HIGH RESOLUTION GRIDS HAVE BEEN PRIMARILY DERIVED FROM A COMPOSITE BLEND OF THE 12 UTC GFS AND REASONABLY COMPATABLE GUIDANCE...AT LEAST AT MID-LARGER SCALES...FROM THE 00 UTC ECMWF/ECMWF ENSEMBLES/GFS ENSEMBLES AND NAEFS ENSEMBLES. THE NATURE OF THE BLEND ACTS TO NOT EMPHASIZE LESS PREDICTABLE SMALLER SCALE FORECAST COMPONENTS AND MAINTAIN MAX CONTINUITY. SCHICHTEL