ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 246 PM EDT SUN JUL 06 2014 VALID 12Z THU JUL 10 2014 - 12Z MON JUL 14 2014 THE 6/00Z ECENS...NAEFS AND GEFS ENSEMBLE MEANS WERE GENERALLY IN AGREEMENT THROUGH THE DAY 5-6 TIME FRAME...EVEN IF THEIR 00Z DETERMINISTIC RUNS WERE AT ODDS WITH THE DEPTH AND SPEED OF ENERGY EXITING THE SOUTHEAST GULF REGION...AND ENTERING THE NORTHWEST GULF. TOOK A LITTLE EXTRA TIME AND WAS ABLE TO GET SOME SMALLER-SCALE DETAILS OF THE DAY 5-8 SURFACE GRAPHICS USING THE 6/12Z CANADIAN AND GFS. WHAT HAS BEEN AND WILL CONTINUE TO BE THE CHALLENGING PART OF THE FORECAST IS THE AMPLITUDE OF THE MID-LATITUDE FLOW PATTERN AT THE SURFACE AND THE OUTCOME OF AN ALEUTIAN TROUGH SLOWLY MIGRATING EASTWARD INTO A 'BLOCKY' UPPER-LEVEL RIDGE PLANTED OVER NORTHEAST ALASKA AND NORTHWEST CANADA. THERE WAS BETTER AGREEMENT BETWEEN THE SOLUTIONS VERSUS 24 HOURS AGO...BUT THE GEFS/CANADIAN ENSEMBLES CONTINUE TO BE THE PROGRESSIVE SOLUTIONS FROM THE EASTERN ALEUTIANS---INTO AND THROUGH THE SOUTH CENTRAL GULF OF ALASKA DURING THIS MEDIUM RANGE PERIOD. IN PART...AND THROUGH DAY 5...THE 6/12Z DETERMINISTIC CANADIAN/GFS AND ECMWF SOLUTIONS LOOKED VERY CLOSE TO THE 00Z MEANS AND ROTATE A SERIES OF WESTWARD-MOVING SHORTWAVES ACROSS THE INTERIOR AND OUT INTO THE EAST CENTRAL BERING SEA ALONG THE UPWIND SIDE OF THE UPPER-LEVEL RIDGE. AND CONSEQUENTLY...ALLOW UNDERCUTTING ENERGY TO RE-ENTER THE SOUTHWEST GULF OF ALASKA ON DAY 5. THAT PART OF THE FORECAST REMAINS ON TRACK. FOR DAY 6...THE 6/12Z DETERMINISTIC GUIDANCE DOES ALLOW THE TROUGH IN THE GULF OF ALASKA TO BECOME RE-ENERGIZED WITH A MODERATELY-INTENSE SURFACE CYCLONE...AND THE COUNTER-CLOCKWISE ROTATION OF SHORTWAVE ENERGY INTO THE PANHANDLE AND SOUTH CENTRAL INTERIOR. THE STORM TRACK...DEPTH AND EVOLUTION OF THIS DAY 6 CYCLONE ARE THE ITEMS THAT PROJECT MUCH OF THE UNCERTAINTY...AND WHY THE MEANS HAD TO BE EQUALLY-WEIGHTED COMPONENTS OF THE FORECAST FOR DAYS 7-8. VOJTESAK