ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 251 PM EDT SUN OCT 26 2014 VALID 12Z THU OCT 30 2014 - 12Z MON NOV 03 2014 AFTER A NUMBER OF DAYS OF GUIDANCE EXHIBITING CONSIDERABLE SPREAD AND RUN TO RUN VARIABILITY... TODAY THERE IS ACTUALLY DECENT CONTINUITY/AGREEMENT WITH AT LEAST THE MEDIUM TO LARGER SCALE ASPECTS OF THE FCST. OF COURSE SOME DETAILS REMAIN TO BE WORKED OUT. THESE INCLUDE LOW PRESSURE THAT MAY LIFT NWD TOWARD THE PANHANDLE THU-FRI... HOW MUCH NRN LATITUDE ENERGY MAY BE PULLED SWWD ACROSS THE MAINLAND AROUND THE UPR RIDGE DRIFTING NEWD FROM EXTREME ERN SIBERIA AND INTERACTION OF THIS ENERGY WITH THE SYSTEM CROSSING THE BERING SEA... AND FINALLY LARGER SCALE TIMING DIFFS ALOFT BY DAY 8 MON. FOR THE WAVE FCST TO TRACK NWD TOWARD THE PANHANDLE LATE THIS WEEK THERE IS STILL WIDE SPREAD AMONG MODELS/ENSEMBLE MEMBERS IN STRENGTH AND TRACK. PREFERENCE FOR A COMPROMISE TRACK AND LACK OF CONFIDENCE IN FORMATION OF A DEEP COMPACT UPR LOW AS PER 00Z ECMWF/CMC SOLNS... LEADING TO DEEP SFC LOWS IN THOSE MDLS... YIELD A WAVE ON THE WEAKER HALF OF THE FULL SPREAD WHILE AWAITING BETTER AGREEMENT. THE ONE POINT OF AGREEMENT IN THE 12Z RUNS IS TOWARD A STRONGER WAVE THAN FCST BY THE 06Z/12Z GFS. PREFERRED BLEND LISTED BELOW SHOWS TIMING CLOSE TO THE 12Z ECMWF/UKMET BUT WITH LESSER DEPTH AND A TRACK SLIGHTLY WWD. LOOKING AT THE COMBINATION OF THE BERING SEA SYSTEM AND MAINLAND FLOW THU INTO SAT... RECENT GFS RUNS AND NOW THE 12Z UKMET ARE GETTING STRONGER WITH NRN LATITUDE ENERGY THAT COULD PROGRESS SWWD FROM THE NRN MAINLAND INTO THE BERING SEA AND INTERACT WITH BERING SEA FLOW. HOWEVER EVEN WITHOUT THE INPUT OF THIS NRN MAINLAND ENERGY THE 00Z ECMWF/CMC AND THEIR ENSEMBLE MEANS AGREE WITH THE 00Z GFS THAT THE PRIMARY SFC LOW OVER THE BERING SEA SHOULD BE SLOWER THAN REMAINING SOLNS. EMPHASIS FOR LOW PRESSURE SHOULD SHIFT E OF THE PENINSULA LATE IN THE PERIOD AS THE MEAN TROUGH ALOFT DRIFTS EWD. BY DAYS 7-8 SUN-MON GUIDANCE HOLDS ONTO THE IDEA OF THE PATTERN AMPLIFYING. AS OF NEXT MON THE ENSEMBLE MEANS SHOW A DEEP TROUGH OVER ERN ASIA WITH A RIDGE NEARING 180 LONGITUDE AND TROUGH EXTENDING FROM THE MAINLAND TO THE S/SW. AT THAT TIME THE 00Z ECMWF/CMC BECOME FASTER THAN THE MEANS WITH THE PROGRESSION OF THESE FEATURES. THE APPARENT EVOLUTION TOWARD A MORE AMPLIFIED PATTERN SEEMS TO FAVOR THE MEANS AT THIS TIME. DAYS 4-7 THU-SUN INCORPORATE VARIED WEIGHTINGS OF BOTH MODEL AND ENSEMBLE MEAN SOLNS TO YIELD THE BEST ACCOUNT FOR FCST UNCERTAINTY WITH A REASONABLE LEVEL OF DETAIL. THE 00Z ECMWF MEAN HAS SLIGHTLY HIGHER WEIGHTING THAN OTHER COMPONENTS THAT INCLUDE THE 00Z GFS/ECMWF AND 06Z GEFS MEAN... AS WELL AS 00Z CMC INTO 12Z DAY 5 FRI. DAY 8 MON THEN ADJUSTS TO AN EVEN BLEND OF THE 06Z GEFS/00Z ECMWF MEANS BASED ON AFOREMENTIONED TIMING DIFFS OF THE LARGE SCALE PATTERN. RAUSCH