MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 315 AM EDT MON AUG 08 2016 VALID AUG 08/0000 UTC THRU AUG 11/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION WITH FINAL PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ FRONT EXTENDING WWD THROUGH THE MID-ATLANTIC REGION THROUGH TUE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE NO SIGNIFICANT MODEL DIFFERENCES WERE NOTED WITH THIS SYSTEM. STAGNANT/PERSISTENT UPPER CIRCULATION ACROSS THE NERN GULF OF MEX ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS / 00Z GEFS / 12Z EC MEAN BLEND CONFIDENCE: BELOW AVERAGE THE 00Z UKMET REMAINS MUCH STRONGER WITH THE MID-LEVEL VORT MAX ALONG THE GULF COAST THROUGH THU...AND THE 00Z ECMWF/CMC REMAIN TOWARD THE STRONGER SIDE OF THE DETERMINISTIC ENVELOPE. ONLY THE ECMWF AND ITS ENSEMBLES SHOW SUPPORT FOR THIS IDEA. UNTIL OTHER DETERMINISTIC/ENSEMBLE TRENDS CAN SUPPORT THE MORE DEVELOPED ECMWF/UKMET/CMC...THE PREFERENCE IS TO BE WEAKER...CLOSER TO THE 00Z GFS AND THE LATEST GEFS/EC MEANS...ALTHOUGH THE 00Z GFS COULD BE TOO WEAK. THE EC MEAN TEMPERS THE STRENGTH OF THE LOW LEVEL LOW COMPARED TO ITS DETERMINISTIC COUNTERPART. GIVEN THE COMPLEXITY OF THE WEAK STEERING CURRENTS...POOR RUN TO RUN MODEL CONSISTENCY...CONFIDENCE REMAINS BELOW AVERAGE WITH THIS SYSTEM...ESPECIALLY WITH RESPECT TO THE FINER DETAILS. REFER TO THE QPFPFD FOR DETAILS CONCERNING THE PREFERRED GUIDANCE FOR QPF. MID-LEVEL VORTICITY MAX OVER THE MID-MISS VALLEY MON MORNING AND TRACKING INTO THE OHIO VALLEY TUE WHILE WEAKENING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON 00Z NAM COMPROMISE CONFIDENCE: SLIGHTLY ABOVE AVERAGE AS WITH ITS PREVIOUS RUNS...THE NAM REMAINS MORE AMPLIFIED WITH THE SHORTWAVE TROUGH MOVING ACROSS THE MID MS VALLEY EARLY TODAY AND IS ON ITS OWN WITH THE DEVELOPMENT OF MID-LEVEL VORTICITY BACK ACROSS WRN KANSAS EARLY TODAY. THE OTHER MODELS HANDLE THE WEAKENING VORT ACROSS THE MISS VALLEY SIMILARLY. REFER TO THE QPFPFD FOR DETAILS CONCERNING THE PREFERRED GUIDANCE FOR QPF. SLOW MOVING CLOSED LOW OVER THE PACIFIC NORTHWEST THROUGH MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ PREFERENCE: NON 00Z UKMET BLEND CONFIDENCE: AVERAGE SINCE YESTERDAY...THE CMC HAS TRENDED FASTER TOWARD THE CONSISTENT ECMWF...AND THE GFS HAS TRENDED A BIT SLOWER TOWARD THE ECMWF. GIVEN THE GROWING CONSENSUS...THE 00Z GFS AND 00Z ECMWF APPEAR TO BE THE BEST COMPROMISE FOR THIS SYSTEM...FOLLOWED CLOSELY BY THE 00Z NAM AND 00Z CMC...DESPITE SOME MINOR WOBBLES IN POSITION FROM RUN TO RUN. THE 00Z UKMET LAGS SIGNIFICANTLY BEHIND THE DETERMINISTIC/ENSEMBLE CLUSTERING. SHORTWAVE TRACKING ACROSS SRN CANADA MON/TUE COLD FRONT MOVING THROUGH THE UPPER MISSISSIPPI VALLEY AND GREAT LAKES TUE/WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ PREFERENCE: 00Z ECMWF / WEAKER VERSION OF THE 00Z GFS CONFIDENCE: AVERAGE THE MODELS SHOW SIMILAR TIMING WITH THE FRONT...ENOUGH FOR A GENERAL MODEL BLEND. THE MOISTURE RETURN IN THE 00Z ECMWF...AHEAD OF AN APPROACHING WRN UPPER TROUGH...APPEARS IMPROVED/HIGHER COMPARED TO ITS 12Z/07 RUN GIVEN STRENGTHENING LOW LEVEL FLOW THROUGH THE PLAINS. THE GFS APPEARS TO HAVE THE RIGHT IDEA BUT MAY SUFFER FROM CONVECTIVE FEEDBACK OVER MN/WI WED NIGHT. SEE THE QPFPFD FOR DETAILS CONCERNING THE PREFERRED GUIDANCE FOR QPF. OTTO www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...