MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 133 PM EST TUE JAN 12 2016 VALID JAN 12/1200 UTC THRU JAN 16/0000 UTC ..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF ...NORTHERN STREAM SHORTWAVE ENERGY TRAVERSING THE GREAT LAKES REGION... ...SURFACE LOW CROSSING THE GREAT LAKES TODAY... ...REDEVELOPING LOW OFF NEW ENGLAND TONIGHT... PREFERENCE: GENERAL MODEL CONSENSUS CONFIDENCE: ABOVE AVERAGE THERE IS GOOD MODEL AGREEMENT WITH THE TIMING/STRENGTH OF AN UPPER TROUGH TO MOVE THROUGH THE OHIO VALLEY LATER TODAY...AND SWINGING ACROSS NEW ENGLAND WITH A NEGATIVE TILT LATE TONIGHT. THE GUIDANCE IS IN GOOD AGREEMENT IN DEPICTING THE MAIN LOW GIVING WAY TO A SECONDARY LOW NEAR THE COAST OF MAINE BY 06Z/13. GIVEN THE GOOD MASS FIELD AGREEMENT IN THE GUIDANCE...A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...SHORTWAVE TRACKING FROM NORTHWEST MEXICO TO THE LOWER RIO GRANDE VALLEY THROUGH THURS... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE GUIDANCE IS IN GOOD AGREEMENT WITH THE MASS FIELD DETAILS OF THE UPPER TROUGH OVER NORTHWEST MEXICO WHICH WILL EJECT EAST ACROSS THE LOWER RIO GRANDE VALLEY THROUGH THURS. THEREAFTER...THIS ENERGY WILL SHEAR OUT TOWARD THE GULF COAST STATES. ...SHORTWAVE DROPPING SOUTHEASTWARD ACROSS THE PLAINS BY WED AND OFFSHORE BY THURS NIGHT... PREFERENCE: BLEND OF THE 12Z GFS AND 12Z ECMWF CONFIDENCE: ABOVE AVERAGE A BLEND OF THE 12Z GFS AND 12Z ECMWF WILL BE MAINTAINED FOR THE TIME BEING WITH THIS SYSTEM BASED ON STRONGER MODEL CLUSTERING AND BETTER RUN TO RUN CONTINUITY. ...UPPER TROUGH/SURFACE WAVE REACHING THE WEST COAST BY EARLY WED... ...ENERGY AMPLIFYING OUT INTO THE PLAINS/MS VALLEY THURS/FRI... PREFERENCE: BLEND OF THE 12Z GFS/12Z UKMET AND 12Z ECMWF...WITH MAIN TROUGH/LOW BLEND OF THE 12Z GFS AND 12Z ECMWF...WITH SOUTHEAST LOW CENTER CONFIDENCE: BELOW AVERAGE THE MODELS BRING AN UPPER TROUGH AND AN ASSOCIATED WAVE OF LOW PRESSURE INTO THE WEST COAST LATER TONIGHT AND EARLY WEDNESDAY...WITH THE ENERGY THEN TRAVERSING THE INTERMOUNTAIN WEST BEFORE DIVING AND AMPLIFYING OUT INTO THE PLAINS ON THURS. ON FRI...THE MODELS SHOW IT CROSSING THE LOWER/MID MS VALLEY AND AIMING FOR THE OH VALLEY. MEANWHILE...LOW PRESSURE IS EXPECTED TO CROSS THE MIDWEST AND APPROACH THE GREAT LAKES REGION LATE FRI...WITH A SECOND AREA OF LOW PRESSURE DEVELOPING OVER THE NORTHERN GULF OF MEXICO AND LIFTING UP ALONG THE SOUTHEAST COAST BY LATE FRI. THE 12Z NAM AND 12Z CMC ARE THE STRONGEST AND SLOWEST SOLUTIONS WITH THIS SYSTEM. THE 12Z ECMWF AND 12Z UKMET ARE RELATIVELY WEAKER AND MORE PROGRESSIVE...AND ALSO TAKE SURFACE LOW PRESSURE FARTHER NORTH INTO THE GREAT LAKES REGION BY FRI VERSUS THE NAM AND CMC WHICH ARE SOUTH DOWN OVER IL. THE 12Z GFS IS IN BETWEEN CAMPS...BUT HAS TRENDED A BIT MORE PROGRESSIVE AND ALSO STRONGER. THE 00Z ECENS MEAN FAVORS THE ECMWF/UKMET CAMP...WITH THE 12Z GEFS MEAN GENERALLY CLOSE TO THE GFS SOLUTION. CONFIDENCE IS LIMITED BASED ON THE OVERALL MODEL SPREAD AS THIS SYSTEM EVOLVES EAST OF THE ROCKIES...BUT WILL PREFER A BLEND OF THE 12Z GFS/12Z UKMET AND 12Z ECMWF AT THIS POINT WITH THE LARGER SCALE TROUGH AND MAIN LOW CENTER NEAR THE GREAT LAKES REGION. THE UKMET APPEARS TO BE A BIT TOO FAR INLAND WITH THE LOW CENTER OVER THE SOUTHEAST....AND SO OVER THIS AREA WILL PREFER A BLEND OF THE GFS AND ECMWF. ...UPPER TROUGH MOVING INTO THE PACIFIC NORTHWEST ON THURS... PREFERENCE: BLEND OF THE 12Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE THE 12Z NAM IS A SLOW OUTLIER WITH THE ENERGY MOVING INTO THE PACIFIC NORTHWEST ON THURS. THE 12Z UKMET ALSO IS A BIT SLOWER THAN THE MODEL CONSENSUS. THE 12Z GFS/12Z ECMWF AND 12Z CMC ARE ALL A BIT FASTER AND HAVE STRONGER CLUSTERING...ALTHOUGH THE 12Z CMC MAY BE A BIT TOO DEEP. THE LATTER CAMP ALSO HAS STRONGER ENSEMBLE SUPPORT...AND THUS WILL PREFER A BLEND OF THE GFS AND ECMWF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON