MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 244 AM EDT WED MAR 19 2014 VALID MAR 19/0000 UTC THRU MAR 22/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NOTE: THE 00Z/19 UKMET APPEARS TO BE IDENTICAL TO ITS 12Z/18 RUN. THE SDM HAS BEEN NOTIFIED...BUT IT DOES NOT APPEAR THE ISSUE CAN BE RESOLVED IN THE NEAR TERM. STORM AFFECTING THE GREAT LAKES AND NORTHEAST TODAY THROUGH THU ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: BLEND OF 21Z SREF MEAN / 00Z ECMWF CONFIDENCE: A LITTLE ABOVE AVERAGE SOME RELATIVELY MINOR STRENGTH/PLACEMENT DIFFERENCES REMAIN WITH THIS SYSTEM...WITH THE 00Z GFS SEEN AS THE FASTEST WITH THE TRACK OF THE SURFACE LOW INTO CANADA EARLY THU...AND THE 00Z UKMET A LITTLE SLOWER THAN THE MODEL CONSENSUS. LARGER DIFFERENCES APPEAR ON THU WITH THE STRENGTH OF A COASTAL LOW THAT MOVES THROUGH NEW ENGLAND IN SOME OF THE GUIDANCE. THE 00Z CMC REMAINS THE MOST DEVELOPED WITH THIS FEATURE...WITH ZERO DETERMINISTIC SUPPORT AND ONLY VERY LITTLE ENSEMBLE SUPPORT FROM THE GLOBAL ENSEMBLE MEMBERS. THE 00Z GFS APPEARS TOO WEAK HOWEVER...WITH THE 00Z ECMWF APPEARING TO SHOW A GOOD MIDDLE GROUND ALONG WITH THE SIMILAR 21Z SREF MEAN. THE 00Z ECMWF IS A BIT QUICKER TO STRENGTHEN THIS LOW ACROSS NEW ENGLAND COMPARED TO ITS 12Z RUN...BUT WHEN BLENDED WITH THE MORE SUBDUED SREF MEAN...A GOOD COMPROMISE IS OFFERED. SYSTEM MOVING FROM THE NORTHWEST TO THE NORTHERN PLAINS/MIDWEST THROUGH FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 70/30 BLEND OF THE 00Z ECMWF/00Z GFS (RESPECTIVELY) CONFIDENCE: BELOW AVERAGE THE GREATEST MODEL DIFFERENCES DEVELOP WITH THIS SYSTEM AS THE LEADING EDGE OF AN UPPER TROUGH REACHES THE NRN PLAINS THU EVENING FROM THE PACIFIC NORTHWEST. THE NAM IS ON THE STRONGER SIDE OF THE GUIDANCE AND SLIGHTLY FASTER THAN THE CONSENSUS...WHILE THE 00Z UKMET/CMC ARE ON THE WEAKER AND SLOWER SIDE OF THE AVAILABLE MODELS...BUT THE 00Z CMC DID ADJUST NORTH AND TOWARD THE STRENGTH OF THE GFS/ECMWF. THE 00Z ECMWF HAS MADE MINOR ADJUSTMENTS FROM ITS 12Z RUN TOWARD THE GFS POSITION/STRENGTH...BUT THESE ADJUSTMENTS ARE SMALL AND EARLIER THINKING STILL HOLDS TRUE. THE 00Z GFS AND 00Z ECMWF ARE IN THE MIDDLE WITH THE 12Z SREF SHOWING SIMILARLY TO THE NAM...WHILE THE EC MEAN AND 00Z CMC SUPPORT A SOLUTION CLOSER TO THE ECMWF. THE GFS/ECMWF SHOW NORTH/SOUTH PLACEMENT DIFFERENCES...BUT ENSEMBLE MEMBERS FROM THE EC/CMC/GEFS AS A WHILE INDICATE GREATER SUPPORT FOR THE ECMWF BY FRI NEAR THE GREAT LAKES...WHICH IS WHY MORE WEIGHT TOWARD THE ECMWF IS PREFERRED...BUT SUBTLE DIFFERENCES ALOFT TRANSLATE TO SIGNIFICANT DIFFERENCES AT THE SURFACE WITH ABOVE AVERAGE MODEL SPREAD DECREASING CONFIDENCE BELOW AVERAGE. www.wpc.ncep.noaa.gov/html/model2.shtml... OTTO