MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 101 AM EDT WED MAY 06 2015 VALID MAY 06/0000 UTC THRU MAY 09/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NCEP MODEL EVALUATION ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SHORTWAVE OVER THE PACIFIC NORTHWEST DROPPING INTO THE SOUTHWEST WED/THU ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/12Z ECMWF CONFIDENCE: ABOVE AVERAGE THE 00Z NAM CONTINUED ITS TREND OF A SLOWER AND DEEPER SOLUTION AS THE SHORT WAVE DROPS INTO THE SOUTHWEST STATES AND CLOSES OFF...ESPECIALLY LATE ON DAY 1 AND PERSISTING INTO DAY 2. THE 00Z GFS...WHILE SHOWING SOME MINOR RUN TO RUN DIFFERENCES...REMAINED FAIRLY STEADY WITH ITS PROGRESSION. SEE NO REASON TO STRAY FAR FROM THE 00Z GFS AND 05/12Z ECMWF COMPROMISE SOLN AT THIS POINT. AS MENTIONED PREVIOUSLY...THE 05/12Z CMC GLOBAL AND UKMET WERE CLOSE TO THE CONSENSUS AS WELL. SHORTWAVE TRACKING FROM THE SOUTHWEST TOWARDS THE CENTRAL PLAINS WED/THU ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~ PREFERENCE: 00Z GFS/12Z ECMWF CONFIDENCE: AVERAGE GIVEN THE RUN TO RUN CONSISTENCY OF THE GFS...AND THE 00Z NAM REMAINING ON SLOWER SIDE OF THE GUIDANCE...NO REASON TO CHANGE THE PREVIOUS PREFERENCE OF THE LATEST GFS WITH THE PREVIOUS ECMWF. LOW PRESSURE NEAR THE SOUTHEAST COAST BY FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 05/12Z ECMWF/CANADIAN...06/00Z GFS CONFIDENCE: BELOW AVERAGE THE 06/00Z NAM AND GFS CLUSTERED TOGETHER INTO EARLY DAY 3 WITH RESPECT TO THE TRACK OF THE SURFACE LOW...WHICH FOR THE GFS REPRESENTED A SLIGHT EASTWARD SHIFT COMPARED WITH THE 05/12Z RUN. THE NAM INTENSITY...HOWEVER...LOOKS A LITTLE SUSPECT. THE ECMWF TAKES THE LOW ON A TRACK TO THE EAST OF THE NAM/GFS WHICH WAS NOT TOO FAR OFF FROM THE PREVIOUS CANADIAN GLOBAL. A QUICK AND INCOMPLETE LOOK AT THE 06/00Z UKMET SHOWS IT TAKING THE LOW NORTHWARD MORE QUICKLY THAN OTHER GUIDANCE AND ON A TRACK TO THE EAST OF THE ECMWF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN