MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 305 AM EDT TUE MAY 05 2015 VALID MAY 05/0000 UTC THRU MAY 08/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z FINAL MODEL EVALUATION...INCLUDING THE CANADIAN/UKMET/ECMWF ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST DROPPING INTO THE SOUTHWEST U.S. WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/00Z ECMWF CONFIDENCE: AVERAGE THE GFS/ECMWF CONTINUED TO SHOW THE BEST AGREEMENT TO THE LATEST ENSEMBLE MEANS AND SPAGHETTI HEIGHT CLUSTERING ACROSS THE WEST BY THU MORNING...WITH NO SIGNIFICANT TRENDS NOTED IN THE ENSEMBLES. THE 05/00Z UKMET WAS A BIT FASTER TO DROP THE ENERGY SOUTHWARD BUT IT QUICKLY GOT BACK CLOSE TO THE MODEL CONSENSUS BY 18Z THU. THE 05/00Z ECMWF WAS ALSO A TAD QUICKER TO DROP THE ENERGY SOUTH WHEN COMPARED WITH PREVIOUS RUNS...AND THEN THE TRACK OF THE LOW REMAINED A BIT EAST OF ITS PREVIOUS RUN. SHORTWAVE TROUGH MOVING FROM THE SOUTHWEST TOWARDS THE CNTRL PLAINS WED/THU ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~ PREFERENCE: 00Z GFS/ECMWF CONFIDENCE: AVERAGE THE 05/00Z GFS/ECMWF WERE IN FAIRLY GOOD AGREEMENT THROUGH 08/12Z...WITH MOST OF THE DIFFERENCES BETWEEN THE TWO MODELS STILL CONFINED TO THE FINAL 12 HOURS OF THE FORECAST WHEN THE MID LEVEL WAVE IS SHARPER/QUICKER THAN IN THE ECMWF. THINK A COMPROMISE OF THE 05/00Z GFS/ECMWF SHOULD MINIMIZE SOME OF THE TIMING DIFFERENCES WHILE STILL BEING RELATIVELY CLOSE TO THE UKMET/CANADIAN. LOW PRESSURE LIKELY NEARING THE SOUTHEAST COAST BY THE MIDDLE/END OF THE WEEK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 04/12Z GFS CONFIDENCE: AVERAGE ECMWF/GEFS/CMC ENSEMBLE SCATTER LOW PLOTS CONTINUED TO SHOW RELATIVELY GOOD CLUSTERING WITH POSITION OVER THEIR PAST FEW 00/12Z CYCLES. THE 05/00Z GFS SFC LOW SHIFTED TO A MORE EASTERLY TRACK...PUTTING IT ON THE EASTERN SIDE OF THE ENVELOPE OF SOLNS. GIVEN THE AGREEMENT AMONG THE ENSEMBLES...THINK THE 12Z GFS FROM MONDAY STILL REPRESENTS A USEFUL OPERATIONAL PROXY FOR THE ENSEMBLE MEANS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN