EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1059 AM EST SUN NOV 06 2016 VALID 12Z WED NOV 09 2016 - 12Z SUN NOV 13 2016 ...OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENT... MODEL GUIDANCE REMAINS IN REASONABLE AGREEMENT WITH THE LONGWAVE PATTERN OVER THE LOWER 48 LATER THIS WEEK AND INTO NEXT WEEKEND...WHICH WILL FEATURE ANOMALOUS RIDING BUILDING BACK INTO THE WESTERN/WEST CENTRAL U.S. WHILE A DOWNSTREAM TROUGH SETS UP OVER THE EASTERN U.S.. MODELS EVEN SEEM TO HAVE A GOOD HANDLE ON SOME OF THE SMALLER SCALE FEATURES IMPACTING THE WESTERN HALF OF THE NATION DURING THE MEDIUM RANGE PERIOD...INCLUDING A SERIES OF SHORTWAVES EXPECTED TO LIFT THROUGH THE PACIFIC NORTHWEST AS WELL AS A BROAD UPPER LOW FORECAST TO RETROGRADE FROM THE SOUTHERN PLAINS TO NORTHERN MEXICO/FOUR CORNERS REGION LATER THIS WEEK. HOWEVER...FORECAST CONFIDENCE QUICKLY DETERIORATES WITH FEATURES OVER THE EASTERN U.S.. EVEN THOUGH MODELS HAVE GENERALLY COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF SHORTWAVE ENERGY ENTERING THE NORTHEAST/MID-ATLANTIC REGION WEDNESDAY...ABOVE AVERAGE SPREAD IN ENSEMBLE MEMBERS AND FLASHES OF MODEL RUNS THAT STILL SPLIT AND DIG A PORTION OF ENERGY SOUTH/SOUTHEASTWARD INTO A CLOSED LOW (SIMILAR TO THE 06Z GFS) SUGGESTS THERE IS STILL A WIDE RANGE OF SOLUTIONS WITH THIS FEATURE. ALSO...THE DETAILS OF AN UPSTREAM SHORTWAVE REACHING THE UPPER MIDWEST/GREAT LAKES THURSDAY NIGHT INTO FRIDAY REMAINS VERY UNCERTAIN...ESPECIALLY AS IT AMPLIFIES OVER THE EASTERN U.S. NEXT WEEKEND. THE WPC DAY 3-7 FORECAST STARTED WITH A BLEND BETWEEN 00Z GFS/GEFS MEAN AND ECMWF ENSEMBLE MEAN...WITH SLIGHTLY MORE WEIGHTING TOWARDS THE ECWMF SINCE IT WAS CLOSER TO THE MIDDLE OF MODEL SPREAD WITH THE INITIAL SHORTWAVE ENTERING THE NORTHEAST/MID-ATLANTIC STATES WEDNESDAY. ...WEATHER HIGHLIGHTS/THREATS... THE LOWER 48 SHOULD CONTINUE TO SEE LESS THAN THE USUAL COVERAGE OF PCPN DURING THE PERIOD. HEAVIEST RNFL WILL LIKELY BE OVER THE NRN PAC NW AND VANCOUVER ISLAND. LATEST CONSENSUS FOR CNTRL-ERN U.S. FLOW ALOFT EARLY-MID PERIOD MAY SUPPRESS SOME OF THE ACTIVITY THAT HAS BEEN FCST ALONG THE GULF COAST. THERE MAY BE A BRIEF EPISODE OF MOSTLY LGT PCPN OVER THE APLCHNS/NORTHEAST MIDWEEK WITH THE LEADING SYSTEM... FOLLOWED BY ANOTHER AREA OF PCPN OVER THE GRTLKS/NORTHEAST AS UPR TROUGHING AMPLIFIES FRI-SUN. COLDER AIR WITH THE LATTER SYSTEM MAY SUPPORT SOME LAKE ENHANCED/LAKE EFFECT PCPN AS WELL AS SNOW OVER PARTS OF THE NORTHEAST. EXISTENCE/TRACK OF A PSBL CLOSED LOW ALOFT WILL HAVE AN INFLUENCE ON PCPN COVERAGE/INTENSITY/TYPE. LOCATIONS FROM THE CNTRL GREAT BASIN THROUGH THE NRN-CNTRL ROCKIES AND NRN PLAINS SHOULD SEE THE MOST EXTREME WARMTH WITHIN A BROAD AREA OF ABOVE NORMAL TEMPS OVER THE WRN-CNTRL U.S.. IN PARTICULAR THE NRN PLAINS MAY SEE HIGHS OF AT LEAST 20-25F ABOVE NORMAL ON WED FOR PSBL RECORD HIGHS AND ANOTHER VERY WARM DAY ON SAT. SOME RECORD WARM LOWS ARE PSBL FROM THE WEST INTO NRN PLAINS ON ONE OR MORE DAYS AS WELL. UPR TROUGHING AMPLIFYING INTO THE EAST BY FRI-SUN WILL DECREASE TEMPS FROM NEAR NORMAL EARLY IN THE PERIOD TO AT LEAST 5-10F BELOW NORMAL OVER SOME AREAS NEXT WEEKEND. GERHARDT