ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 249 PM EDT SUN SEP 14 2014 VALID 12Z THU SEP 18 2014 - 12Z MON SEP 22 2014 THE 14/00Z ECENS AND 14/06Z GEFS ENSEMBLE MEANS SERVED AS THE BASELINE FOR THE DAY 4 THROUGH DAY 8 ALASKA MEDIUM RANGE PACKAGE. THIS ENSEMBLE CONSENSUS PULLS THE BULK OF THE UPPER-LEVEL CIRCULATION ACROSS THE EASTERN ALEUTIANS AND INTO THE NORTHWEST GULF OF ALASKA BETWEEN 18/18Z AND 19/12Z---AND ONE COULD USE THE DETERMINISTIC SOLUTIONS UNTIL LATE DAY 5/EARLY DAY 6---WHEN THE INDIVIDUAL SHORTWAVES ROTATING THROUGH THE BASE OF THE UPPER-LEVEL TROUGH BEGIN TO ALTER THE TIMING...DEPTH AND TRAJECTORY OF SECONDARY CYCLOGENESIS. WITH THE MEANS IN RATHER GOOD AGREEMENT...MINIMAL ALTERATIONS WERE MADE TO THE SURFACE GRAPHICS THROUGH DAY 7. THE DAY 8 GRAPHIC DOES INDICATE A WEAKER CYCLONE IN THE GULF OF ALASKA AND A COOLER AIRMASS APPROACHING THE STATE FROM THE NORTHWEST (NORTHEAST SIBERIA). VOJTESAK