MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1227 PM EDT MON MAR 14 2016 VALID MAR 14/1200 UTC THRU MAR 18/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...UPPER LOW TRACKING INTO THE OH VALLEY/MID ATLANTIC... ...SURFACE LOW DEVELOPMENT ALONG MID-ATLANTIC COAST TUES... PREFERENCE: 12Z GFS CONFIDENCE: AVERAGE THE MODELS ALL TAKE THE COMPACT CLOSED LOW CURRENTLY MOVING INTO THE OH VALLEY OFF TO THE EAST AND INTO THE MID-ATLANTIC REGION THROUGH TONIGHT AND EARLY TUES. THE ENERGY IS EXPECTED TO FOSTER SURFACE CYCLOGENSIS OFF THE DELMARVA WHICH WILL THEN LIFT NORTHEAST OFF SOUTHERN NEW ENGLAND LATER TUES. THE 12Z NAM AND 00Z CMC ARE A BIT FARTHER LEFT WITH THE LOW TRACK OFF THE MID-ATLANTIC AND NEW ENGLAND ON TUES VERSUS THE MODEL CONSENSUS. THE 00Z ECMWF IS FARTHEST EAST AND AWAY FROM THE COAST...WITH THE 00Z UKMET ALSO TENDING TO BE EAST OF THE MODEL CONSENSUS. THE 12Z GFS SPLITS THE DIFFERENCE BETWEEN CAMPS AND SINCE IT GENERALLY REFLECTS THE MODEL CONSENSUS...THE 12Z GFS WILL BE PREFERRED. ...DEVELOPING BROAD CLOSED LOW OVER THE NORTHERN PLAINS/MIDWEST/GREAT LAKES... ...DEEPENING SURFACE LOW PRESSURE IMPACTING THE REGION... PREFERENCE: BLEND OF THE 06Z GEFS MEAN AND 00Z ECENS MEAN CONFIDENCE: BELOW AVERAGE MULTIPLE SHORTWAVE IMPULSES TRAVERSING THE NORTHWEST THROUGH TODAY AND TONIGHT WILL LEAD TO THE DEVELOPMENT OF A BROAD CLOSED LOW OVER THE NORTHERN PLAINS BY LATER TUES BEFORE THEN GRADUALLY ELONGATING EASTWARD ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION WED AND THURS. THE HEIGHT FALLS WILL GENERATE A DEEPENING SURFACE LOW CENTER OVER THE NORTHERN PLAINS WHICH WILL THEN GRADUALLY ADVANCE EAST TOWARD THE GREAT LAKES REGION WED AND THURS. THIS UPPER LOW WILL BECOME PART OF A LARGER SCALE REX BLOCK INVOLVING SOUTHERN CANADA AND THE GREAT LAKES REGION BY THE END OF THE PERIOD WHICH WILL RESULT IN THE SURFACE LOW SLOWING DOWN CONSIDERABLY. THE 12Z GFS ALTHOUGH IT HAS TRENDED SLOWER...STILL IS ONE OF THE MORE PROGRESSIVE SOLUTIONS IN TAKING HEIGHT FALLS INTO THE GREAT LAKES REGION. CONSEQUENTLY...THIS RESULTS IN A SOMEWHAT MORE PROGRESSIVE SURFACE LOW/FRONT. THE 00Z CMC SOLUTION IS THE SLOWEST SOLUTION AND FOCUSES MUCH MORE LOW PRESSURE UP OVER THE UPPER MS VALLEY VERSUS THE GREAT LAKES REGION THROUGH TUES AND WED. THE 12Z NAM/00Z UKMET AND 00Z ECMWF ARE ALL A LITTLE SLOWER THAN THE GFS IN PIVOTING ENERGY UP ACROSS THE GREAT LAKES REGION. THE 06Z GEFS MEAN STILL FAVORS THE SOMEWHAT MORE PROGRESSIVE DETERMINISTIC GFS AS A WHOLE...BUT THE 00Z ECENS MEAN SUGGESTS THAT THE DETERMINISTIC ECMWF MAY BE A TAD TOO SLOW AND DEEP. WILL KEEP CONTINUITY FOR NOW AND CONTINUE TO LEAN TOWARD AN ENSEMBLE MEAN APPROACH BY BLENDING THE GEFS MEAN AND ECENS MEAN. ...AMPLIFYING SHORTWAVE DROPPING OUT OF WESTERN CANADA THURS... PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE A WELL AGREED UPON DEEP LAYER RIDGE IS EXPECTED TO BE FOCUSED ALONG AND JUST OFFSHORE THE WEST COAST AND EXTENDING NORTH UP INTO THE GULF OF AK BY WED AND THURS. AS THE RIDGE AMPLIFIES...SHORTWAVE ENERGY OVER NORTHERN BRITISH COLUMBIA IS EXPECTED TO DROP SOUTHWARD ALONG THE EAST SIDE OF THE RIDGE AND DOWN INTO THE INTERMOUNTAIN WEST. THE 00Z UKMET IS THE WEAKEST AND MOST PROGRESSIVE SOLUTION...WITH THE 12Z NAM THE SLOWEST AND STRONGEST. THE 12Z GFS AND 00Z ECMWF CLUSTER TOGETHER RATHER WELL AND GENERALLY REFLECT THE MULTI-MODEL CONSENSUS. THEREFORE 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