ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1226 PM EDT WED SEP 23 2015 VALID 12Z SUN SEP 27 2015 - 12Z THU OCT 01 2015 THE 06Z/23 GFS LAGS THE 00Z/23 ECMWF, ECENS MEAN, AND NAEFS MEAN WITH THE PROGRESSION OF THE WAVE ACROSS THE SOUTHERN BERING SEA SUNDAY AND MONDAY--A KEY SYSTEM AT THE MEDIUM RANGE FOR THE ALASKA REGION. A MAJOR TREND IN THE GUIDANCE SINCE THE 00Z/22 MODEL CYCLE IS TOWARD NORTHERN STREAM DOMINANCE, WITH THE DOOR SEEMINGLY SHUT TO TYPHOONAL-INFUSED CYCLONES EAST OF THE DATE LINE AFTER THIS WEEKEND'S INCORPORATION ACROSS THE ALEUTIANS. THE BULK OF THE RECENT GUIDANCE PROGS A SPRAWLING, ENERGETIC NORTHERN-STREAM WAVE--CROSSING THE NORTHERN KURIL ISLANDS TUESDAY--TO LIFT INTO THE OUTER ALEUTIANS BY NEXT THURSDAY. THE 00Z/23 ECMWF IS SUFFICIENTLY HARMONIOUS WITH THE RECENT ENSEMBLE MEANS TO USE AS A TEMPLATE INTO THE MIDDLE OF NEXT WEEK, WITH A PROGRESSIVE INCORPORATION OF THE ECENS MEAN WITH TIME AFTER ABOUT 12Z TUESDAY SEPTEMBER 29. THEREAFTER, THE OPERATIONAL ECMWF IS DIFFERENT ENOUGH FROM ITS ATTENDANT MEAN OVER THE NEAR-SHORE ARCTIC AND ALONG THE NORTH SLOPE TO MERIT A MANUAL BLEND DOMINATED BY THE ENSEMBLES. CISCO