MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 147 PM EST WED NOV 05 2014 VALID NOV 05/1200 UTC THRU NOV 09/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF ALL 12Z MODEL GUIDANCE ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ...UPPER TROF LIFTING THROUGH INTERIOR NEW ENGLAND DURING THE NEXT COUPLE HOURS... FINAL PREFERENCE: ANY OF THE LATEST MODEL SOLUTIONS FORECAST CONFIDENCE: HIGH THIS MORNING AN UPPER TROF WAS SEEN LIFTING ACROSS INTERIOR NEW ENGLAND UP INTO NOVA SCOTIA. MODELS ARE IN FULL AGREEMENT OVER THIS SHORT DURATION OF TIME SO WILL RECOMMEND ANY OF THE LATEST MODEL SOLUTIONS. ...CLOSED LOW SPINNING OVER CENTRAL MEXICO... FINAL PREFERENCE: MODEL COMPROMISE BETWEEN THE 12Z NAM/GFS/ECMWF FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE WATER VAPOR IMAGERY INDICATED A BROAD CYCLONIC CIRCULATION ANCHORING THE WESTERN COAST OF MEXICO. ABUNDANT MOISTURE STREAMING AHEAD OF THIS SYSTEM CONTINUES TO MIGRATE INTO THE SOUTHERN PLAINS/LOWER MS VALLEY PROVIDING EXTENSIVE CLOUD COVER AND WIDESPREAD RAINFALL. MODELS REMAIN ADAMANT ABOUT KEEPING THIS UPPER LOW NEARLY STATIONARY AS IT BECOMES CUT-OFF FROM THE PREVAILING WESTERLIES. THROUGH 07/0000Z...THE BIGGEST OUTLIERS ARE THE 12Z/00Z CMC WHICH ALLOWS THE CIRCULATION TO DRIFT WESTWARD. THIS SEEMED TO BE THE BIAS OF THE CMC DURING ITS PAST SEVERAL RUNS. TO VARYING DEGREES...THE OTHER MODELS ARE FAIRLY CONSISTENT IN ALLOWING THE SYSTEM TO DRAG EASTWARD EVOLVING MORE INTO AN OPEN WAVE SOUTH OF THE RIO GRANDE. THE AGREEMENT IS MUCH BETTER THAN RECENT DAYS WHERE A BULK OF THE ECMWF ENSEMBLE MEMBERS SUGGESTED SOMETHING MUCH SLOWER PER SPAGHETTI DIAGRAMS. WILL LEAN ON THE CONSENSUS OF THE 12Z NAM/GFS/ECMWF BUT NOT INCLUDE THE 12Z UKMET AS IT WAS SLOWER AT TIMES...PARTICULARLY AT THE END OF THE PERIOD. CONFIDENCE IS DEFINITELY HIGHER THAN PREVIOUS DAYS THOUGH. ...AMPLIFYING TROF AFFECTING THE NORTHEASTERN U.S. ON THURSDAY/FRIDAY... ...PAIR OF SURFACE LOWS/ASSOCIATED FRONTAL BOUNDARIES... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF/UKMET FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE AN AREA OF HEIGHT FALLS CURRENTLY MOVING THROUGH THE NORTHERN PLAINS WILL GRADUALLY GAIN AMPLITUDE WHILE TRAVERSING ACROSS THE UPPER GREAT LAKES LATER TONIGHT AND INTO TOMORROW MORNING. DURING THIS PROCESS...A SECONDARY AREA OF LOW PRESSURE IS FORECAST TO DEVELOP BETWEEN 06/1200Z AND 06/1800Z ACROSS THE CENTRAL APPALACHIANS. AT THIS POINT...MODELS AGREE ON THE INITIAL SURFACE LOW WEAKENING OVER THE LOWER GREAT LAKES WHILE THE LEAD CYCLONE FURTHER DEVELOPS ACROSS THE COASTAL MID-ATLANTIC. BY 07/0000Z...THE ENSEMBLE LOW PLOTS SHOW ONLY MINIMAL SPREAD WHICH LOOKS BETTER THAN THE PREVIOUS TWO MODEL CYCLES. LOOKING ALOFT...AGREEMENT IS REASONABLE THROUGH MUCH OF THURSDAY BUT DETAIL DIFFERENCES ARE NOTED THEREAFTER. THE 12Z NAM IS A TAD QUICKER WITH THE LEAD ENERGY CROSSING COASTAL NEW ENGLAND RELATIVE TO THE WELL CLUSTERED MEANS. THIS SPREAD INCREASES IN TIME SO WILL LEAN AWAY FROM SUCH A SOLUTION. OVERALL THE 12Z GFS/ECMWF/UKMET PROVIDE A REASONABLE GUIDE HERE AND SEEMS TO SETTLE WELL WITHIN THE CENTER OF THE FORECAST SPREAD. WPC WILL FAVOR A BLEND OF THE 12Z GFS/ECMWF/UKMET. ...PROGRESSIVE SHORTWAVE MOVING FROM THE PACIFIC NORTHWEST TO THE NORTHERN TIER... ...ASSOCIATED SURFACE FEATURES... FINAL PREFERENCE: MODEL COMPROMISE BETWEEN THE 12Z GFS/ECMWF/UKMET FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE THE MID-LATITUDE FLOW WILL BE QUITE AMPLIFIED WITH BROAD UPPER RIDGING ACROSS THE INTERMOUNTAIN WEST/ROCKY MOUNTAIN REGION EARLY THURSDAY. NEARLY ZONAL FLOW ACROSS THE EASTERN PACIFIC WILL KEEP THE FLOW PROGRESSIVE WITH ONE KEY IMPULSE RACING TOWARD THE PACIFIC NORTHWEST COAST THURSDAY MORNING. THE SYSTEM SHOULD QUICKLY LOSE AMPLITUDE AS IT ENCOUNTERS THE STRONG RIDGING DOWNSTREAM. THE MODELS ARE IN DECENT AGREEMENT THROUGH THURSDAY WITH THE 12Z CMC NOW MERGING WITH THE REST OF THE GUIDANCE. LATER ON...THE SYSTEM INTERACTS WITH SOME NORTHERN STREAM ENERGY FROM CENTRAL CANADA WHICH ALLOWS A LONGWAVE TROF TO DIG THROUGH THE CENTRAL U.S. AND MS RIVER VALLEY. AT THE SURFACE...THE 12Z NAM TRAILS SOME OF THE OTHER SOLUTIONS WITH THE PLACEMENT OF THE PROGRESSIVE COLD FRONT. IT SEEMS LIKE THE 12Z GFS/ECMWF/UKMET LEAN CLOSEST TO THE ENSEMBLE MEANS BUT THERE IS ENOUGH MODEL SPREAD TO KEEP THE CONFIDENCE AT SLIGHTLY BELOW AVERAGE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RUBIN-OSTER