MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 150 PM EST SUN NOV 08 2015 VALID NOV 08/1200 UTC THRU NOV 12/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF ...DEVELOPING CLOSED LOW OVER THE MID MS VALLEY... ...MOVING ACROSS THE OH VALLEY AND NORTHEAST... ...LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO... ...LIFTING NORTHEAST TO THE MID-ATLANTIC/NEW ENGLAND... PREFERENCE: BLEND OF THE 12Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE A ELONGATED AXIS OF SHORTWAVE ENERGY CURRENTLY OVER THE CENTRAL AND SOUTHERN PLAINS WILL AMPLIFY INTO A CLOSED LOW CENTER OVER THE MID MS VALLEY BY MON AND THEN EJECT EAST-NORTHEAST ACROSS THE OH VALLEY AND INTO THE NORTHEAST TUES AND WED WHILE GRADUALLY WEAKENING. THIS ENERGY WILL PLAY A ROLE IN THE EVOLUTION OF LOW PRESSURE EJECTING NORTHEAST OUT OF THE NORTHERN GULF OF MEXICO ...WHICH IS EXPECTED TO LIFT NORTHEAST ACROSS THE SOUTHEAST COASTAL PLAIN AND ESSENTIALLY REDEVELOP ALONG THE MID-ATLANTIC COAST TUES BEFORE LIFTING INTO SOUTHERN NEW ENGLAND BY WED. THE 12Z NAM IS A STRONGER OUTLIER SOLUTION WITH THE CLOSED LOW FEATURE AS IT MOVES ACROSS THE NORTHERN MID-ATLANTIC AND NEW ENGLAND TUES AND WED. CONSEQUENTLY...IT TENDS TO TUCK SURFACE LOW PRESSURE A LITTLE LEFT OF THE MULTI-MODEL CONSENSUS AND IS PERIODICALLY A BIT STRONGER. THE NAM ALSO APPEARS TO BE A LITTLE TOO FAST WITH ITS LOW EVOLUTION. THE 12Z GFS/12Z CMC AND 12Z ECMWF ARE NOW PRETTY WELL CLUSTERED WITH A LOW TRACK A BIT RIGHT OF THE NAM AND ESPECIALLY AFTER 60 HOURS. THE 12Z GEFS MEAN SUPPORTS THE GFS-LED CONSENSUS. THE 12Z UKMET IS NOW THE MOST PROGRESSIVE SOLUTION WITH THE HEIGHT FALLS AND GRADUALLY THE SURFACE LOW. WILL PREFER A BLEND OF THE 12Z GFS AND 12Z ECMWF AT THIS POINT. ...DEEP UPPER TROUGH CROSSING THE WESTERN U.S. AND EJECTING TOWARD THE MIDWEST... ...STRENGTHENING SURFACE CYCLONE ACROSS THE CENTRAL PLAINS/MIDWEST... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE AMPLIFIED FLOW ACROSS THE NORTHEASTERN PACIFIC WILL GRADUALLY TRANSLATE DOWNSTREAM WITH A DEEP UPPER TROUGH EXPECTED TO CROSS THE WESTERN U.S. MON AND TUES BEFORE THEN EJECTING VIGOROUSLY OUT INTO THE CENTRAL PLAINS AND THEN THE MIDWEST BY WED. A STRONG AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE CO HIGH PLAINS LATE TUES AND LIFT TOWARD IA ON WED. THE MODELS ON THE LARGER SCALE ARE NOW IN VERY GOOD AGREEMENT...AND THUS A GENERAL MODEL COMPROMISE WILL BE PREFERRED TO RESOLVE ANY SMALLER SCALE DIFFERENCES AT THIS POINT. ...NORTHERN STREAM SYSTEM MIGRATING THROUGH THE DAKOTAS... PREFERENCE: 12Z GFS CONFIDENCE: AVERAGE A MUCH WEAKER NORTHERN STREAM FEATURE MAKES ITS WAY THROUGH THE DAKOTAS BY MIDDAY TUES. THE 12Z CMC IS LIKELY TOO DEEP WITH THIS SYSTEM...AND EVEN THE 12Z UKMET APPEARS TO BE A TAD TOO DEEP AT LEAST WITH ITS SURFACE REFLECTION OVER THE DAKOTAS. THE 12Z ECMWF IS LIKELY A LITTLE TOO WEAK. THE 12Z GFS OFFERS A NICE COMPROMISE SOLUTION WHICH IS REASONABLY CLOSE TO THE 12Z NAM. ...PROGRESSIVE SHORTWAVE REACHING THE PACIFIC NORTHWEST BY WED... PREFERENCE: NON-NAM CONSENSUS CONFIDENCE: ABOVE AVERAGE A RATHER PROGRESSIVE SHORTWAVE AND ASSOCIATED COLD FRONT WILL CROSS THE NORTHWEST ON WED. THE 12Z NAM IS NOTED AS BEING PERHAPS A TAD TOO STRONG ALOFT BY WED AS THE ENERGY MOVES ACROSS THE NORTHERN ROCKIES. WILL PREFER A NON-NAM CONSENSUS WITH THE REMAINING MODELS APPEARING TO BE WELL CLUSTERED NOW WITH TIMING AND DEPTH. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON