ALASKA EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 200 PM EDT TUE APR 22 2014 VALID 12Z SAT APR 26 2014 - 12Z WED APR 30 2014 MOST GUIDANCE EXPECTS AN ELONGATED AREA OF LOWER HGTS ALOFT... EXTENDING FROM THE SRN BERING SEA E/SEWD AS OF EARLY SAT... TO CONSOLIDATE INTO A MEAN CLOSED LOW THAT SHOULD LINGER OVER THE NERN PAC FOR MOST OF THE PERIOD. SOLNS DIFFER A LITTLE MORE WITH THE PATTERN OVER THE MAINLAND WITH A MODERATE MAJORITY SHOWING MODEST RIDGING EXTENDING INTO THE MAINLAND FROM NWRN CANADA VERSUS GFS/GEFS MEAN RUNS THAT MAINTAIN MORE OF A WEAKNESS ALOFT. SFC LOW CLUSTERING FROM THE ERN ALEUTIANS/PENINSULA INTO THE NERN PAC IS NOT YET AS GOOD AS DESIRED. ON DAY 4 SAT THE 00Z ECMWF/CMC ARE WELL WWD OF THE 00Z/06Z/12Z GFS AND 00Z/06Z GEFS MEAN WITH SFC LOW PRESSURE BUT THE 00Z CMC MEAN IS EVEN FARTHER WWD. THUS FAR THERE IS NOT ENOUGH CONTINUITY TO GO WITH THE FARTHEST WWD SOLNS... BUT THE 00Z ECMWF MEAN HAS MADE A DECENT NWWD ADJUSTMENT SINCE PRIOR RUNS AND PROVIDES A GOOD STARTING POINT IN LIGHT OF CURRENT SPREAD. THE NEXT UNCERTAINTY IS THE ULTIMATE EVOLUTION OF NRN PAC ENERGY THAT FLOWS AROUND THE SRN/ERN PERIPHERY OF THE NERN PAC UPR LOW. RECENT OPERATIONAL MODEL RUNS SUGGEST POTENTIAL FOR THE ENERGY ALOFT TO SUPPORT A COMPACT NWD MOVING SFC SYSTEM THAT COULD BRUSH THE PANHANDLE AROUND DAYS 6-7 MON-TUE. THIS IS A TRACKABLE FEATURE ORIGINATING FROM THE SHORT RANGE SO ENHANCING AN INITIALLY PREFERRED 00Z ECMWF ENSEMBLE MEAN FCST TO INCLUDE AT LEAST A WEAK WAVE SEEMS REASONABLE. UPSTREAM FOCUS WILL BE ON PSBL STREAM INTERACTION THAT MEDIUM RANGE GUIDANCE TENDS TO HAVE DIFFICULTIES WITH... IN THIS CASE NRN STREAM ENERGY TRACKING OUT OF ASIA AND ACROSS KAMCHATKA ALONG WITH A SEPARATE SRN STREAM WRN PAC SYSTEM THAT BECOMES DETACHED FROM THE WESTERLIES EARLY IN THE FCST. CURRENTLY ECMWF/CMC MODEL AND ENSEMBLE GUIDANCE AS A WHOLE COMPARES BETTER TO CONTINUITY IN BEING LESS AMPLIFIED/MORE PROGRESSIVE WITH THE NRN STREAM SYSTEM RELATIVE TO 00Z-06Z GFS/GEFS SOLNS. IN SOME WAYS THE 12Z GFS SHOWS SOME 00Z ECMWF-LIKE ADJUSTMENTS BUT CONFIDENCE IN DETAILS REMAINS BELOW AVERAGE. THE MAJORITY SCENARIO LEADS TO MORE EMPHASIS ON BERING SEA SFC LOW PRESSURE VERSUS HAVING A SLOW MOVING SYSTEM TO THE S OF THE WRN ALEUTIANS THROUGH NEXT TUE-WED. THE 00Z ECMWF MEAN HAS SLOWED SOMEWHAT COMPARED TO PREVIOUS RUNS SO IT PROVIDES A GOOD INTERMEDIATE SOLN BETWEEN THE FASTER 00Z CMC/CMC MEAN AND LESS PROBABLE 00Z-06Z GFS/GEFS MEAN. RAUSCH