MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1252 PM EDT SUN AUG 07 2016 VALID AUG 07/1200 UTC THRU AUG 11/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION WITH PRELIMINARY 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: BLEND OF THE GFS/00Z ECMWF CONFIDENCE: BELOW AVERAGE TO VARYING DEGREES...MOST OF THE MODELS TAKE A SHORTWAVE SOUTH OF THE LOW THAT IS IN THE NORTHERN GULF AND MOVE IT ACROSS SOUTHERN FL LATE SUN BEFORE LIFTING IT BACK TO THE NORTH ALONG THE EASTERN FL COAST ON FRI...AND THEN BRINGING BACK TO THE WEST INTO SOUTHERN GA. THE NAM MAY BE A LITTLE OVERDEVELOPED WITH THIS FEATURE...DEVELOPING A SECOND CLOSED SYSTEM OFF OF THE NORTHERN FL/GA COAST THAT IS NOT WELL SUPPORTED BY THE OTHER GUIDANCE. MEANWHILE MOST OF THE GUIDANCE WEAKENS THE LOW IN THE NORTHERN GULF BEFORE RESTRENGTHENING/REDEVELOPING FURTHER TO THE WEST AS ENERGY FROM THE NORTH DROPS INTO THE NORTHERN GULF. 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 TRACKING THROUGH THE CNTRL PLAINS TODAY AND INTO THE MID-MISS VALLEY MON MORNING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: BLEND OF THE GFS/00Z ECMWF CONFIDENCE: SLIGHTLY BELOW AVERAGE AS WITH ITS PREVIOUS RUNS...THE NAM REMAINS MORE AMPLIFIED WITH THE SHORTWAVE TROUGH MOVING ACROSS THE CENTRAL PLAINS SUN INTO THE MID MS VALLEY EARLY MON. WITH RESPECT TO ITS TIMING AND AMPLITUDE...THE GFS AND 00Z ECMWF REMAIN IN BETTER AGREEMENT AGREEMENT. REFER TO THE QPFPFD FOR DETAILS CONCERNING THE PREFERRED GUIDANCE FOR QPF. SLOW MOVING CLOSED LOW OVER THE PACIFIC NORTHWEST THROUGH MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ PREFERENCE: BLEND OF THE GFS/00Z ECMWF CONFIDENCE: AVERAGE MODELS HAVE COME INTO A LITTLE BETTER AGREEMENT WITH THE UPPER LOW MOVING ACROSS THE NORTHWEST. HOWEVER THE NAM STARTS TO MOVE TO THE LEADING EDGE OF THE GUIDANCE AS THE CENTER REACHES SOUTHERN SASKATCHEWAN LATE WED. HOWEVER...A BIGGER OUTLIER AT THE MOMENT IS THE 00Z UKMET...WHICH IS CONSIDERABLY SLOWER THAN THE OTHER DETERMINISTIC MODELS. COLD FRONT TRACKING THROUGH THE UPPER MISS VALLEY AND GREAT LAKES TUE/WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ PREFERENCE: NON-00Z UKMET BLEND CONFIDENCE: AVERAGE THE 00Z UKMET IS SLOWER WITH THE MID/UPPER LEVEL SHORTWAVE AND ASSOCIATED SURFACE WAVE THAT IS FORECAST TO MOVE FROM WESTERN INTO CENTRAL CAN LATE MON INTO EARLY TUE. FROM THERE ONWARD IT IS SLOWER WITH COLD FRONT AS IT MOVES ACROSS THE NORTHERN PLAINS/UPPER MIDWEST/GREAT LAKES TUE-WED. OTHERWISE THE DETERMINISTIC MODELS SHOW GENERALLY GOOD AGREEMENT WITH THIS SYSTEM. PEREIRA www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...