ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 332 PM EDT FRI JUL 10 2015 VALID 12Z TUE JUL 14 2015 - 12Z SAT JUL 18 2015 WPC ALASKAN MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH ASSOCIATED HIGH RESOLUTION SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM A 60/40 BLEND OF THE 00 UTC ECMWF/NAEFS ENSEMBLE MEANS. MANUAL ADJUSTMENTS WERE APPLIED TO THE SMOOTHED BLEND TO ADD OFFSHORE SURFACE LOW DEPTH CONSISTENT WITH SYSTEM SUPPORT EXPECTED ALOFT. ENSEMBLE MEANS AND ESPECIALLY THE DETERMINISTIC MODELS CONTINUE TO STRUGGLE WITH DOWNSTREAM RIPPLE EFFECTS ASSOCIATED WITH UNCERTAIN FLOW AMPLIFICATIONS WITHIN A PRONOUNCED NRN STREAM FLOW OUT FROM NRN ASIA AND ALSO WITH NEXT WEEKS MID-HIGH LATITUDE ENTRAINMENT OF THE EXTRATROPICAL REMNANTS OF CURRENT WRN PACIFIC TYPHOON CHAN-HOM. FORECAST UNCERTAINTY IS GREATER THAN NORMAL...BUT FLOW PATTERNS TEND TO AMPLIFY WHEN TROPICAL SYSTEMS ARE ENTRAINED IN THE HIGHER LATITUDE FLOW. THE WPC GUIDANCE BLEND ACCORDINGLY USED AN ENSEMBLE MEAN FORECAST APPROACH AND A 60/40 BLEND OF THE 00 UTC ECMWF/NAEFS ENSEMBLE MEANS OFFERS A SOLUTION SOMEWHAT ON THE MORE AMPLIFIED SIDE OF THE FULL ENVELOPE OF SOLUTIONS. THIS SEEMS MOST CONSISTENT WITH WPC ALASKAN CONTINUITY. SCHICHTEL