EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 244 AM EDT SAT NOV 05 2016 VALID 12Z TUE NOV 08 2016 - 12Z SAT NOV 12 2016 ...OVERVIEW AND GUIDANCE/UNCERTAINTY ASSESSMENT... WITHIN A STABLE AND AMPLIFIED E-CNTRL PAC RIDGE/W-CNTRL NOAM RIDGE/EAST COAST TROUGH PATTERN... GUIDANCE IS CONTINUING TO HAVE DIFFICULTIES IN RESOLVING THE EVOLUTION OF ENERGY REACHING THE CNTRL U.S./EXTREME SRN CANADA BY LATE IN THE SHORT RANGE PERIOD WITH THE DIFFS EXPANDING OVER THE MEDIUM RANGE PERIOD. DIVERGENCE OF SOLNS BEGINS WHILE THE ENERGY IS GENERALLY WITHIN THE LARGE SCALE MEAN RIDGE WHICH IS A SCENARIO THAT CAN LEAD TO FCST DIFFICULTIES. TOWARD THE END OF THE PERIOD THERE ARE ALSO MEANINGFUL DIFFS WITH UPSTREAM ENERGY FCST TO REINFORCE THE EAST COAST TROUGH. MOST GUIDANCE FROM THE 12Z/18Z CYCLES HAD SETTLED INTO A MORE AGREEABLE EVOLUTION FOR THE CNTRL U.S. ENERGY... PULLING DOWN ENOUGH ENERGY TO HELP FORM A CLOSED LOW REACHING NEAR THE SRN AZ/NM BORDER BY DAY 4 WED BUT WITH HIGHER HGTS THAN WHAT SOME PRIOR SOLNS HAD DEPICTED OVER OR NEAR THE PLAINS. THIS IS A PLAUSIBLE EVOLUTION GIVEN THAT THE UPR LOW WOULD BE FAIRLY FAR REMOVED FROM THE CORE OF POSITIVE HGT ANOMALIES NEAR THE U.S.-CANADIAN BORDER AND COULD LOOSELY BE ACCOUNTED FOR WITHIN TELECONNECTION-FAVORED FLOW RELATIVE TO THE DOMINANT ERN PAC/NOAM HGT ANOMALY CENTERS. BASED ON THE TEMPORARILY IMPROVED CLUSTERING FOR THE CNTRL U.S./SRN ROCKIES AND THE NEED TO RESOLVE LINGERING TIMING/AMPLITUDE DIFFS FOR REMAINING ENERGY THAT CROSSES THE NORTHEAST/MID ATLC... THE UPDATED FCST STARTED WITH AN EVEN BLEND AMONG THE 18Z GFS/GEFS MEAN AND 12Z ECMWF/ECMWF MEAN FOR DAYS 3-5 TUE-THU. PERHAPS NOT SURPRISINGLY THE NEW 00Z GUIDANCE PROVIDES SIGNIFICANT DIFFS WITH THE UKMET BACK TO A DEEP ERN PLAINS CLOSED LOW AND THE GFS CLOSING OFF A LOW NEAR THE EAST COAST. THE GFS FCST CONFLICTS WITH RECENT GUIDANCE TRENDS TOWARD THE E COAST SHRTWV ON WED BEING SOMEWHAT FLATTER AND FASTER. GIVEN THE TIME FRAME GUIDANCE OFFERS A DECENT SIGNAL TOWARD A MORE SUBSTANTIAL SHRTWV AMPLIFYING TOWARD THE EAST COAST BY NEXT FRI-SAT... BUT WITH VARIOUS IDEAS ON WHETHER/WHERE A CLOSED LOW MAY FORM. THE 12Z GFS WAS WELL WWD OF MOST OTHER SOLNS WITH ITS CLOSED LOW. OTHER OPERATIONAL MODEL RUNS WERE SOMEWHERE NEAR THE EAST COAST WITHIN THE CONSENSUS TROUGH AXIS. LACK OF CONFIDENCE IN A SPECIFIC MODEL RUN FAVORED THE 18Z GEFS/12Z ECMWF MEANS FOR DAYS 6-7 FRI-SAT THOUGH A SMALL WEIGHTING OF THE 12Z ECMWF WAS MAINTAINED AS IT COMPARED SOMEWHAT BETTER TO THE MEANS THAN THE 18Z GFS. GUIDANCE DIFFS ALONG THE PAC NW COAST REMAIN FAIRLY MODEST. A WEAK EJECTING SHRTWV SHOULD BRUSH THE REGION AROUND TUE NIGHT-WED. THEN UPSTREAM HGT FALLS SHOULD GRADUALLY HEAD INTO THE NORTHWEST. THE INTERMEDIATE FCST PROVIDED BY AN AVG OF THE MEANS TOWARD FRI-SAT APPEARS REASONABLE BASED ON OFFSETTING FACTORS OF THE AMPLIFIED PATTERN VS FAST UPSTREAM PAC FLOW. ...WEATHER HIGHLIGHTS/THREATS... DEEP LAYERED SOUTHERLY FETCH OF MSTR AHEAD OF THE E-CNTRL PAC MEAN TROUGH WILL SUPPORT POTENTIAL FOR SOME LOCALLY HEAVIER RNFL NEAR THE PAC NW COAST WITH HIGHEST TOTALS LIKELY OVER THE OLYMPICS AND VANCOUVER ISLAND. THE CENTRAL GULF COAST IS ANOTHER AREA WITH DECENT CONFIDENCE FOR SOME HVY RNFL TOTALS WITH POTENTIALLY SLOW MOVEMENT OF ACTIVITY. HOWEVER THERE IS STILL UNCERTAINTY IN PRECISE LOCATION DUE TO DEPENDENCE ON EXACT DETAILS OF MID LVL FLOW OVER THE ERN 2/3 OF THE CONUS AND POSN OF ONE OR MORE SFC TROUGHS THAT MAY ENHANCE LOW LVL CONVERGENCE. LOWER CONFIDENCE AREAS THAT REQUIRE MONITORING INCLUDE THE SRN ROCKIES/HIGH PLAINS... WHICH WILL BE SENSITIVE TO DEPTH/LOCATION OF THE PSBL NEARBY UPR LOW... AND NEAR THE EAST COAST WHERE THERE IS CLOSED LOW POTENTIAL. EVEN OTHER AREAS OF THE CNTRL-ERN STATES COULD END UP WITH SOME FOCUSED RNFL BASED ON THE SPREAD ALOFT AMONG INCOMING MODELS AND RECENT ENSEMBLES. EXPECT THE MOST ANOMALOUS WARMTH TO REMAIN ACROSS THE WEST INTO THE NRN-CNTRL PLAINS/MS VLY WITH BROAD COVERAGE OF HIGHS 10-20F ABOVE NORMAL. DAILY RECORDS FOR HIGHS/WARM LOWS ARE PSBL BUT CURRENTLY DO NOT APPEAR TO BE WIDESPREAD. TEMPS NEAR THE EAST COAST SHOULD GRAVITATE TOWARD NEAR/BELOW NORMAL LEVELS FRI-SAT AS UPR TROUGHING DEEPENS. RNFL OVER PARTS OF THE SRN HIGH PLAINS/GULF COAST MAY ALSO KEEP HIGHS NEAR TO BELOW NORMAL OVER THOSE AREAS. RAUSCH