MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 230 PM EDT MON MAR 10 2014 VALID MAR 10/1200 UTC THRU MAR 14/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM GLOBAL AND THE ECMWF ...UPPER LOW REACHING SOUTH TEXAS AND OPENING UP AS IT CROSSES THE GULF COAST STATES... PREFERENCE: NON-GFS CONSENSUS CONFIDENCE: ABOVE AVERAGE THE 12Z GFS IS SEEN AS A BIT OF A FAST OUTLIER WITH THIS SYS...ESP AS IT BEGINS SHEARING OUT ACROSS THE GULF COAST STATES TUES AND WED. THE REMAINING MODELS SHOW REASONABLY GOOD AGREEMENT WITH THIS ENERGY...AND SO WILL PREFER A NON-GFS CONSENSUS ATTM. ...DEEP LOW CENTER/NEG-TILTED TROUGH IMPACTING THE EASTERN U.S. THROUGH THURS... PREFERENCE: BLEND OF THE 12Z GFS/12Z ECMWF...THROUGH WED BLEND OF THE 12Z ECMWF/12Z UKMET...FOR THURS CONFIDENCE: AVERAGE OVERALL...THE MODEL SPREAD REMAINS REASONABLY LOW REGARDING THIS EVOLVING STORM SYS OVER THE NEXT FEW DAYS. ALL OF THE MODELS SHOW A DEEP TROUGH AMPLIFYING OVER THE EASTERN U.S. OVER THE NEXT FEW DAYS...WHICH WILL DRIVE A RAPIDLY INTENSIFYING SFC LOW CENTER EAST OUT OF THE CNTRL PLAINS TUES AND THEN RAPIDLY NEWD INTO SRN NEW ENGLAND BY WED NIGHT. THE STORM SYS SHOULD EXIT INTO SERN CANADA ON THURS. A WIDESPREAD AND RATHER HIGH IMPACT PCPN EVENT...INCLUDING SIGNIFICANT WINTER WX CAN BE EXPECTED IN ASSOC WITH THE EVOLVING DEEP LOW CENTER. PLS CONSULT THE LATEST QPFPFD AND QPFHSD FOR DETAILS CONCERNING THE PCPN IMPACTS. THE 12Z GEM GLOBAL AND 12Z NAM ARE FASTER AND RELATIVELY WEAKER COMPARED TO THE GLOBAL MODEL CONSENSUS WITH RESPECT TO THE EVOLVING SFC LOW. THE 12Z ECMWF/12Z UKMET AND NOW THE 12Z GFS ARE A BIT SLOWER. THE 12Z UKMET AND ESP THE 12Z GFS NOT ONLY TRENDED SLOWER...BUT ARE ALSO NOTABLY STRONGER AT THE SFC AND ALOFT. THE 12Z GFS AND 12Z ECMWF SHOW REASONABLY GOOD AGREEMENT TUES AND WED...BUT THEREAFTER THE GFS BECOMES VERY AGGRESSIVE WITH ITS AMPLIFICATION OF THE NEG-TILTING TROUGH...AND SUGGESTS A STRONG CLOSED LOW CENTER CROSSING THE INTERIOR OF NEW ENGLAND. THE GFS WOULD APPEAR TO BE A BIT TOO STRONG BY THURS AND TOO SLOW. BY THURS...THE ECMWF/UKMET CAMP SPLITS THE DIFF BETWEEN THE STRONGER/SLOW GFS AND THE FASTER/RELATIVELY WEAKER NAM/GEM GLOBAL. BASED ON THE LATEST MODEL TRENDS AND SPREAD...WILL FAVOR A GFS/ECMWF BLEND THROUGH WED...AND THEN LEAN TWD A ECMWF/UKMET BLEND FOR THURS. ...CLIPPER WITH STRONG SURFACE REFLECTION REACHING NEW ENGLAND TONIGHT AND EARLY TUES... PREFERENCE: BLEND OF THE 12Z GFS/12Z ECMWF CONFIDENCE: ABOVE AVERAGE THIS QUICK MOVING SYSTEM CARRIES A SURFACE LOW ACROSS QUEBEC...AND A SECONDARY LOW PRESSURE CENTER MAY DEVELOP OFF THE COAST OF MAINE...WITHIN A SOUTHEASTWARD EXTENSION OF THE SURFACE TROUGH ASSOCIATED WITH WARM ADVECTION AND HEIGHT FALLS AHEAD OF THE UPPER SYSTEM. THE 12Z UKMET AND 12Z GEM GLOBAL DO NOT INDICATE MUCH COASTAL DEVELOPMENT. THE 12Z NAM/12Z GFS AND 12Z ECMWF ALL SUPPORT THE IDEA OF A MORE DEFINED SECONDARY LOW CENTER. THE LATEST GEFS MEAN AND ECENS MEAN SUPPORT THIS IDEA AS WELL. THE NAM AGAIN APPEARS TO BE A LITTLE SLOW OFFSHORE NEW ENGLAND AS SECONDARY LOW PRESSURE EVOLVES. CONSEQUENTLY...WILL PREFER A BLEND OF THE GFS AND ECMWF. ...UPPER LOW CENTER DEVELOPING OVER THE SOUTHWEST... PREFERENCE: BLEND OF THE 12Z ECMWF/12Z UKMET/12Z GEM GLOBAL CONFIDENCE: SLIGHTLY BELOW AVERAGE THE 12Z NAM IS NOTABLY STRONGER WITH THE DEVELOPING CLOSED UPR LOW OVER THE SOUTHWEST WED AND THURS COMPARED TO THE 12Z GFS AND THE NON-NCEP SOLNS. THE 12Z GFS THOUGH APPEARS TO BE A TAD WEAKER/FASTER THOUGH TO BRING HT FALLS INTO THE FOUR CORNERS REGION. THE 12Z UKMET/12Z GEM GLOBAL AND 12Z ECMWF ARE ALL SLOWER. THE LATEST GEFS MEAN AND ECENS MEAN TEND TO SUPPORT THE SLOWER NON-NCEP CONSENSUS. THE STRONGEST MODEL CLUSTERING TENDS TO RESIDE WITH THE ECMWF/GEM GLOBAL AND UKMET OVERALL...SO WILL PREFER A BLEND OF THESE SOLNS...BUT WITH CONFIDENCE A BIT LIMITED. ...PACIFIC SHORTWAVE AFFECTING THE PACIFIC NORTHWEST AND NORTHERN ROCKIES BY WED... ...SURFACE LOW PRESSURE CROSSING SOUTHERN CANADA... PREFERENCE: BLEND OF 12Z ECMWF/12Z UKMET/12Z GEM GLOBAL CONFIDENCE: SLIGHTLY BELOW AVERAGE THE MODELS CONTINUE TO ADVERTISE THE ARRIVAL OF A PAC SHORTWAVE TROUGH ON WED ACROSS PORTIONS OF THE PAC NORTHWEST AND MOVING INTO THE NRN ROCKIES BY THURS. THE 12Z GEM GLOBAL AND 12Z NAM ARE A BIT SLOWER THAN THE GLOBAL MODEL CONSENSUS...WITH THE 12Z UKMET THE MOST PROGRESSIVE. THE 12Z GFS AND 12Z ECMWF SPLIT THE DIFF...BUT THE GFS IS NORTH OF THE ECMWF WITH RESPECT TO THE SFC LOW DETAILS OVER SRN CANADA. THE UKMET ALSO APPEARS AS IF IT MAY BE A LITTLE TOO WEAK WITH THE LOW DEVELOPMENT. THE LATEST GEFS MEAN IS ACTUALLY FASTER THAN THE DETERMINISTIC GFS AND TENDS TO SUPPORT THE FASTER UKMET. MEANWHILE...THE LATEST ECENS MEAN IS A LITTLE FASTER AND NORTH OF THE DETERMINISTIC ECMWF. THE STRONGEST MODEL CLUSTERING TENDS TO FAVOR THE 12Z GFS AND 00Z ECENS MEAN...SO WILL PREFER A BLEND OF THESE SOLNS WITH CONFIDENCE A BIT LIMITED BASED ON THE SPREAD WITH THE SFC LOW TRACK IN SRN CANADA. www.wpc.ncep.noaa.gov/html/model2.shtml... ORRISON