ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 159 PM EDT SUN APR 06 2014 VALID 12Z THU APR 10 2014 - 12Z MON APR 14 2014 TODAYS FCST IS HIGHLIGHTED BY BETTER CLUSTERING OF GUIDANCE AS GFS/GEFS MEAN RUNS HAVE TRENDED STRONGER/SLOWER WITH THE RIDGE ALOFT BUILDING OVER THE MAINLAND AND SLOWER WITH UPSTREAM ALEUTIANS/PACIFIC ENERGY HEADING INTO THE RIDGE... WHILE THE OPERATIONAL ECMWF HAS TRENDED AWAY FROM BLOCKY SOLNS MORE EXTREME THAN INDICATED BY ECMWF MEAN RUNS. THERE IS ALSO IMPROVED AGREEMENT WITH THE DEEP SYSTEM TRACKING FROM THE WRN PAC INTO THE ALEUTIANS THOUGH THE 00Z/06Z GEFS MEANS ARE ON THE FAST SIDE OF THE SPREAD FROM LATE THIS WEEK INTO THE WEEKEND. EARLY IN THE FCST PERIOD... CONSENSUS IS SLIGHTLY WEAKER THAN CONTINUITY WITH A WAVE EXPECTED TO BE NEAR THE PANHANDLE AS OF 12Z THU. UPSTREAM THE 00Z ECMWF MEAN OFFERS A GOOD COMPROMISE BETWEEN THE FARTHER NWD 00Z-06Z GFS/GEFS MEAN RUNS AND SWD 00Z ECMWF/CMC-CMC MEAN SOLNS FOR LOW PRESSURE NEAR THE ALEUTIANS THU-FRI. TRENDS OVER THE PAST 1-2 DAYS FAVOR LEANING AWAY FROM THE NRN SIDE OF THE FULL GUIDANCE SPREAD BUT ECMWF MEAN CONTINUITY DOES NOT YET FAVOR ADJUSTING THE TRACK TO THE S OF THE ALEUTIANS. MEANWHILE THERE HAVE BEEN HINTS FROM GUIDANCE THAT ENERGY FLOWING AROUND THE PERIPHERY OF THE CNTRL PAC TROUGH ALOFT WOULD SUPPORT DEVELOPMENT OF A FRONTAL WAVE... AND NOW THE PAST COUPLE ECMWF MEAN RUNS GENERALLY SUPPORT THE IDEA OF OPERATIONAL RUNS THAT BRING A SFC LOW TO THE PENINSULA OR ERN ALEUTIANS BY AROUND 12Z SAT. SUCH A TRACK FROM THE E-CNTRL PAC INTO THE SERN BERING SEA IS PSBL GIVEN THE STRENGTH/SHAPE OF THE DOWNSTREAM RIDGE THOUGH IT APPEARS THERE WILL BE A FINE LINE BTWN THIS TRACK AND HAVING THE WAVE REMAIN FARTHER SWD. AS WAS THE CASE FOR THE ALEUTIANS LOW... THE 00Z ECMWF MEAN IS IN THE MIDDLE OF THE OPERATIONAL MODEL SPREAD. THE 12Z GFS ADJUSTED TO THE PREFERRED TRACK OVER THE ALEUTIANS THU INTO FRI WHILE IT NOW HOLDS THE PAC WAVE TO THE S OF THE PENINSULA FOR AN EXTRA DAY. MODELS/ENSEMBLE MEANS AGREE THAT THE FRONT ANCHORED BY THE DEEPENING WRN PAC SYSTEM LATE THIS WEEK SHOULD RACE EWD INTO THE ALEUTIANS BY THE WEEKEND WHILE THE CORE OF THE SYSTEM REMAINS WELL WWD. ALONG THIS FRONT 00Z-06Z-12Z GFS AND 00Z ECMWF/CMC RUNS ALL DEVELOP A WAVE BTWN 50-55N LATITUDE BY 12Z SUN AND WHILE NOT UNREASONABLE... WOULD LIKE TO SEE A LITTLE MORE MODEL CONTINUITY AND ENSEMBLE AGREEMENT BEFORE DEPICTING A WAVE AS DEFINED AS SEEN IN THE OPERATIONAL RUNS. BY LATE IN THE PERIOD THE 00Z ECMWF MEAN BECOMES A LITTLE FASTER THAN THE 00Z-06Z GEFS/00Z CMC MEANS AS THE PARENT SYSTEM REACHES THE ALEUTIANS. DIFFS ARE STILL FAIRLY SMALL RELATIVE TO POTENTIAL DAY 8 ERRORS SO A COMPROMISE BETWEEN THE ECMWF MEAN AND NAEFS MEAN IS PREFERRED. FROM DAY 4 THU INTO DAY 6 SAT PARTIAL INCLUSION OF THE 06Z GFS/00Z ECMWF HELPS TO DEEPEN THE PREFERRED INTERMEDIATE SOLN OF THE 00Z ECMWF MEAN TO THE SW OF THE MAINLAND... WHILE THE RESULTING BLEND REPRESENTS CONSENSUS WELL ELSEWHERE. OPERATIONAL MODEL INPUT IS REDUCED DAY 7 SUN AND ELIMINATED DAY 8 MON AS CONFIDENCE DECREASES IN SMALLER SCALE DETAILS AND A 00Z NAEFS/ECMWF MEAN BECOMES PREFERRED TO RESOLVE DIFFS IN TIMING OF THE ALEUTIANS LOW AND STRENGTH OF THE MAINLAND RIDGE ALOFT. RAUSCH