ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 218 PM EDT TUE JUN 24 2014 VALID 12Z SAT JUN 28 2014 - 12Z WED JUL 02 2014 A REASONABLE CONSENSUS OF MODEL/ENSEMBLE GUIDANCE SHOWS A MEAN CLOSED LOW JUST SW OF THE PANHANDLE AND A MEAN RIDGE OVER NWRN CANADA... WITH ONLY GRADUAL CHANGES IN SHAPE/POSN DURING THE PERIOD. UPSTREAM FLOW SHOULD BECOME BROADLY CYCLONIC ACROSS SIBERIA AND INTO THE NWRN MAINLAND WHILE FARTHER SWD A RIDGE AND TRAILING TROUGH/PSBL EMBEDDED UPR LOW SHOULD GRADUALLY PROGRESS ACROSS THE WRN-CNTRL PACIFIC/ALEUTIANS. WITHIN THE FAIRLY AGREEABLE LARGE SCALE EVOLUTION THERE ARE SOME QUESTION MARKS FOR DETAILS ALOFT PRIMARILY OVER/W OF THE MAINLAND. AT THE START OF THE FCST THERE IS STILL A DECENT AMOUNT OF SPREAD WITH A MEDIUM TO SMALL SCALE UPR LOW FCST TO BE OVER THE WRN OR NRN MAINLAND AS OF 12Z SAT. THE 00Z GFS TOOK THIS ENERGY WELL NE OF CONSENSUS SO IT IS DISCOUNTED. THE 12Z RUN IS A LITTLE SWD OF THE MAJORITY CLUSTER. ANOTHER DETAIL ISSUE INVOLVES ENERGY APPROACHING THE WRN MAINLAND BY EARLY DAY 5 SUN. GFS/ECMWF CONTINUITY HAS GENERALLY FAVORED PULLING SOME OF THIS ENERGY SEWD ACROSS THE ERN BERING SEA ON ITS WAY TOWARD THE NERN PAC UPR LOW BUT THE 00Z ECMWF RUN TRACKS THIS ENERGY FARTHER EWD OVER THE MAINLAND. RECENT 6-HRLY GFS RUNS HAVE BEEN SOMEWHAT ERRATIC BUT THE 12Z VERSION HAS REVERTED BACK TO PREVAILING CONTINUITY. THIS APPEARS TO BE A HIGHLY SENSITIVE AREA SO PREFER A BLEND OF THE 12Z GFS AND RECENT ENSEMBLE MEANS THAT ARE RATHER WEAK. BY MID-LATE PERIOD EXACT EVOLUTION OF THE NERN PAC UPR LOW WILL DEPEND ON IF/HOW IT INCORPORATES ANY NRN STREAM ENERGY AND ALSO PSBLY A PORTION OF A CNTRL PAC SHRTWV TROUGH. MOST SOLNS SUGGEST ENERGY ALOFT WILL WEAKEN OR BE PULLED SEWD ENOUGH TO RESULT IN A FAIRLY DIFFUSE SFC REFLECTION OVER THE NERN PAC BY DAY 8 WED. FARTHER WWD THERE IS BETTER THAN AVG CLUSTERING WITH A WRN PAC SYSTEM THAT MAY BEGIN TO AFFECT THE WRN ALEUTIANS LATE IN THE PERIOD. BY NEXT TUE-WED PREFER TO LEAN TOWARD THE MORE STABLE ENSEMBLE MEANS AS SOME OPERATIONAL MODELS BEGIN TO TREND A LITTLE FASTER THAN THE ENSEMBLE MEANS. DAYS 4-6 SAT-MON INCORPORATE IDEAS FROM THE 06Z GEFS/00Z ECMWF MEANS AS WELL AS 12Z-06 GFS/00Z ECMWF TO ADD SOME OPERATIONAL DEFINITION ESPECIALLY FOR THE NERN PAC SFC LOW. EACH OPERATIONAL RUN HAS SUFFICIENTLY LOW WEIGHTING TO DOWNPLAY LOWER CONFIDENCE DETAILS. DAYS 7-8 TUE-WED ARE PRIMARILY WEIGHTED TOWARD THE ENSEMBLE MEANS GIVEN THEIR AGREEMENT IN THE LARGE SCALE PATTERN. RAUSCH