MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 252 AM EDT MON MAY 04 2015 VALID MAY 04/0000 UTC THRU MAY 07/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...00Z MODEL EVALUATION INCLUDING THE CANADIAN/UKMET/ECMWF... ...TROUGH OVER CENTRAL CANADA... PREFERENCE: AFTER 00Z WED...GFS OR ECMWF CONFIDENCE: ABOVE AVERAGE MODEL MASS FIELDS WERE IN GOOD AGREEMENT THROUGH THE DAY ON TUESDAY. AT THAT POINT THE NAM/CMC BECAME MORE AMPLIFIED THAN OTHER MODELS. GIVEN THE CONTINUED LACK OF SUPPORT FOR THEIR SOLUTION...RECOMMEND EITHER THE GFS OR ECMWF. SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST DROPPING INTO THE SOUTHWEST U.S. WED... PREFERENCE: GFS/ECMWF CONFIDENCE: AVERAGE THERE WAS GOOD MODEL AGREEMENT INTO EARLY WEDNESDAY AND THE 04/00Z MODEL RUNS GENERALLY KEPT CONTINUITY WITH THEIR PREVIOUS RUNS. STARTING WEDNESDAY MORNING...THE 04/00Z ECMWF DROPPED A CLOSED MID LEVEL LOW SOUTHWEST TOWARDS THE SOUTHWEST U.S. WHICH WAS DEEPER AND QUICKER THAN ITS EARLIER RUNS. WHILE NOT QUITE AS STRONG AND NOT QUITE AS FAST...THIS IS MORE IN LINE WHICH THE GFS SHOWED. THE UKMET WAS A DEEP/FAST WESTERN OUTLIER. GIVEN THE AGREEMENT WITH THE GFS AND THE ENSEMBLE MEAN...COMBINED WITH MORE AGREEMENT FROM THE ECMWF...THINK A GFS/ECMWF COMPROMISE IS BEST. ...SHORTWAVE TROUGH MOVING ACROSS THE SOUTHWEST MON-TUE/CENTRAL PLAINS WED... MODELS REMAIN IN GOOD AGREEMENT ON THE LARGE SCALE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN