EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1053 AM EST SUN NOV 02 2014 VALID 12Z WED NOV 05 2014 - 12Z SUN NOV 09 2014 ...PATTERN OVERVIEW AND GUIDANCE EVALUATION/PREFERENCES... THE WPC MEDIUM RANGE PRODUCT SUITE HAS BEEN PRIMARILY DERIVED FROM A COMPOSITE BLEND OF REASONABLY COMPATABLE GUIDANCE FROM THE 06 UTC GEFS MEAN WITH THE 00 UTC GFS/ECMWF AND ECMWF ENSEMBLE MEAN. RECENT GUIDANCE HAS BEEN STABLE IN FORECASTING A MEAN PATTERN CONSISTING OF A RIDGE NEAR OR JUST INLAND FROM THE WEST COAST AND A TROUGH OVER THE ERN HALF OF THE LOWER 48. THERE IS FAIR AGREEMENT IN PRINCIPLE WITH INDIVIDUAL NRN STREAM SYSTEMS FROM THE ERN PAC THROUGH THE CONUS BUT WITH SOME TYPICAL DETAIL DIFFS... WHILE SRN TIER SPECIFICS REMAIN UNCERTAIN. IMMEDIATELY BEHIND A SHRTWV BRUSHING THE NORTHEAST AT THE START OF THE PERIOD DAY 3 WED... UPSTREAM PLAINS/MS VLY ENERGY WILL AMPLIFY INTO THE EAST AND SUPPORT A STRENGTHENING SFC LOW REACHING THE NORTHEAST BY DAY 5 FRI. THUS FAR A CONSENSUS APPROACH HAS BEEN THE MOST RELIABLE WAY TO MINIMIZE CONTINUITY CHANGES AND RESOLVE ONGOING SPREAD AND RUN TO RUN VARIABILITY FROM INDIVIDUAL MODELS. THE WPC BLEND LEANS/TRENDS SOME WHAT MORE AMPLIFIED AND LESS PROGRESSIVE THAN CONTINUITY. UPSTREAM OVER THE ERN PAC THERE ARE STILL SOME TIMING/DETAIL DIFFS WITH THE SHRTWV FCST TO REACH THE PAC NW/BC COAST ON THU. AT THE VERY LEAST WOULD TEND TO LEAN AWAY FROM THE STRONGEST SCENARIO SINCE THE FEATURE IS HEADING INTO A MEAN RIDGE. THIS SYSTEM SHOULD EMERGE OVER THE PLAINS AND SRN CANADA BY FRI AND PUSH A COLD FRONT SEWD THEREAFTER. BY DAY 7 SUN THE MODEL/ENSEMBLE SPREAD NEAR THE WEST COAST INCREASES DUE TO DIFFS WITH A SHRTWV TO APPROACH/REACH THE WEST COAST AND SIGNIFICANT FURTHER UPSTREAM UNCERTAINTIES WITH WEST PACIFIC SUPER TYPHOON NURI. THE FCST OVER THE SRN TIER CONTINUES TO HAVE LESS PREDICTABILITY... WITH MEANINGFUL SPREAD ALREADY BEGINNING TO DEVELOP WITH INITIAL SRN PLAINS/NRN MEXICO ENERGY AS OF EARLY DAY 3 WED. GFS-BASED GUIDANCE STILL TENDS TO PULL LESS ENERGY BACK INTO NWRN MEXICO THAN THE GUIDANCE AVG... THOUGH OTHER SOLNS SEEM TO BE TRENDING SOMEWHAT WEAKER WITH THEIR UPR LOW. ON THE POSITIVE SIDE THERE APPEARS TO BE ENOUGH AMPLITUDE TO THE ERN TROUGH BY THU-FRI THAT DIFFS ARISING EARLY IN THE PERIOD MAY BE SUPPRESSED FOR AT LEAST SOME PERIOD OF TIME. ...SENSIBLE WEATHER HIGHLIGHTS... UNCERTAINTY WITH EXACT DETAILS FOR FLOW ALOFT OVER THE SRN TIER LEADS TO LOWER THAN DESIRED CONFIDENCE WITH MID-LATE WEEK COVERAGE/TIMING/INTENSITY OF LOCALLY HVY RNFL THAT MAY BE IN PROGRESS AT THE START OF THE PERIOD OVER/NEAR THE SRN PLAINS IN THE VICINITY OF A WAVY SFC FRONT. POTENTIAL STILL EXISTS FOR ACTIVITY TO BE ENHANCED BY SOME INPUT OF MSTR FROM ERN PAC T.S. VANCE. THEN ATTENTION TURNS TO THE CLIPPER TYPE SYSTEM THAT SHOULD DEVELOP INTO A FAIRLY STRONG SFC LOW OVER THE NORTHEAST BY LATE IN THE WEEK...BRINGING BREEZY TO WINDY CONDS AND ORGANIZED PCPN WITH SOME WRAP-BACK SNOWS ON THE WRN PERIPHERY OF THE MSTR SHIELD FROM THE GREAT LAKES STATES THROUGH THE N-CENTRAL APPALACHIANS TO THE INTERIOR NORTHEAST. MEANWHILE...THE MEAN RIDGE OVER THE WEST COAST SHOULD KEEP PCPN ON THE LIGHT SIDE AND MAINLY CONFINED TO THE PAC NW/NRN ROCKIES. SCHICHTEL