MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1246 PM EDT SAT OCT 03 2015 VALID OCT 03/1200 UTC THRU OCT 07/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...CLOSED LOW OVER THE SOUTHEASTERN U.S... PREFERENCE: BLEND OF THE 00Z UKMET AND 00Z ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE ON THE LARGER SCALE...THE MODELS ARE IN RELATIVELY GOOD AGREEMENT AT THIS POINT WITH THE EVOLUTION OF THE UPPER LOW/TROUGH CROSSING THE SOUTHEAST U.S. THROUGH SUN AND THEN OFFSHORE THE SOUTHEAST COASTLINE THROUGH TUES. HOWEVER...THE 12Z GFS HAS TRENDED A LITTLE FARTHER SOUTH COMPARED TO YESTERDAY WITH THE CLOSED LOW ITSELF...AND IS A TAD SOUTH OF THE GLOBAL MODEL CONSENSUS AS A RESULT. THIS RESULTS IN A SOMEWHAT MORE SUPPRESSED SURFACE LOW/FRONTAL ZONE JUST OFFSHORE THE SOUTHEAST COAST SUN AND MON. MEANWHILE...THE 00Z CMC IS A TAD NORTH OF THE SAME MODEL CONSENSUS...WITH THE 12Z NAM/00Z ECMWF AND 00Z UKMET ALL CLUSTERED TOGETHER IN BETWEEN. THE 12Z NAM THOUGH GRADUALLY BECOMES A LITTLE DEEPER THAN ALL OF THE MODELS OFFSHORE THE SOUTHEAST BY MON AND TUES. GIVEN MODEL CONTINUITY AND CLUSTERING...A BLEND OF THE 00Z UKMET AND 00Z ECMWF WILL BE PREFERRED. ...HEIGHT FALLS CROSSING NORTHERN NEW ENGLAND/SOUTHEAST CANADA... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS SHOW A NORTHERN STREAM SHORTWAVE TROUGH CROSSING NORTHERN NEW ENGLAND THROUGH TODAY...AND THEN QUICKLY ACROSS THE CANADIAN MARITIMES THROUGH SUN.SAT. THERE IS ENOUGH MODEL AGREEMENT THAT A GENERAL MODEL COMPROMISE CAN BE PREFERRED AT THIS POINT. ...ENERGY LIFTING THROUGH THE NORTHERN ROCKIES/HIGH PLAINS THROUGH TONIGHT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE SHORTWAVE ENERGY EJECTING ACROSS THE NORTHERN ROCKIES AND HIGH PLAINS WILL CONTINUE TO LIFT NORTHEAST THROUGH TONIGHT WHILE GRADUALLY DAMPENING OUT TOWARD FAR SOUTHERN CANADA. THE MODELS ARE WELL CLUSTERED OVERALL WITH THEIR MASS FIELDS...AND THUS A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...STRONG CLOSED LOW DROPPING SOUTH DOWN THE WEST COAST THROUGH SUN... ...REACHING THE SOUTHWEST/FOUR CORNERS REGION MON AND TUES... PREFERENCE: BLEND OF THE 00Z UKMET/00Z ECENS MEAN CONFIDENCE: SLIGHTLY BELOW AVERAGE GIVEN A RELATIVELY STRONG MID/UPPER LEVEL RIDGE THAT HAS DEVELOPED OFF THE WEST COAST...A COMPACT BUT ROBUST MID/UPPER LOW WHICH IS NOW OVER THE PACIFIC NORTHWEST WILL BE RACING SOUTHWARD DOWN THE WEST COAST AND INTO THE SOUTHWEST BY MON BEFORE THEN GRADUALLY SHIFTING EAST TOWARD THE FOUR CORNERS REGION ON TUES. THE 00Z ECMWF DROPS ITS CLOSED LOW THE FARTHEST SOUTH THROUGH THE SOUTHWEST...WITH THE 00Z UKMET A LITTLE FARTHER NORTH...AND THE 12Z GFS EVEN A LITTLE FARTHER NORTH OVER PORTIONS OF THE GREAT BASIN. BY TUES...THE 00Z CMC AND 12Z NAM ARE THE FARTHEST NORTH. THE 00Z ECMWF MAY BE TOO FAR SOUTH AND ESPECIALLY SINCE THE 00Z ECENS MEAN IS A LITTLE FARTHER NORTH. THIS COUPLED WITH THE FACT THE 12Z GFS TRENDED A LITTLE BIT NORTH COMPARED TO ITS RUNS YESTERDAY...A PREFERENCE IN BETWEEN THE 12Z GFS AND 00Z ECMWF...AND CLOSE TO THE 12Z UKMET/00Z ECENS MEAN SOLUTIONS WILL BE PREFERRED. ...SHORTWAVE TROUGH CROSSING THE NORTHERN PLAINS ON MON... PREFERENCE: BLEND OF THE 12Z NAM AND 12Z GFS CONFIDENCE: AVERAGE THE MODELS SHOW A NORTHERN STREAM SHORTWAVE TROUGH CLIPPING THE NORTHERN PLAINS REGION BY MON. THE 00Z ECMWF IS FASTER THAN THE MULTI-MODEL CONSENSUS...WITH THE 00Z UKMET AND 00Z CMC THE SLOWEST. THE 12Z NAM AND 12Z GFS SPLIT THE DIFFERENCE AND CLUSTER TOGETHER IN BETWEEN...AND A BLEND OF THESE TWO SOLUTIONS WILL BE PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON