MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 146 AM EST THU MAR 10 2016 VALID MAR 10/0000 UTC THRU MAR 13/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... FINAL 00Z MODEL EVALUATION...INCLUDING THE ECMWF ...DEEP CLOSED LOW CROSSING NORTHERN MEXICO THROUGH THURS... ...SURFACE BOUNDARY EXTENDING NORTHEASTWARD FROM THE SOUTHERN PLAINS INTO THE NORTHEASTERN U.S.... PREFERENCE: 10/00Z GFS CONFIDENCE: AVERAGE THE 00Z NAM CONTINUED ITS IDEA FROM THE PAST FEW RUNS OF LIFTING THE LOW NORTHWARD BY FRIDAY MORNING INTO A POSITION NORTH OF THE MODEL CONSENSUS AND REMAINS A RELATIVE OUTLIER UNTIL LATE FRI. ONE OF THE CONSEQUENCES OF THIS IS THAT DEFORMATION DRIVEN PRECIPITATION IS DRIVEN DEEPER INTO OK/MO THAN THE OTHER MODELS. WITH RESPECT TO THE SURFACE BOUNDARY...THE 00Z NAM SHIFTED SLIGHTLY TO THE NORTH COMPARED WITH ITS 09/12Z RUN...PARTICULARLY WITH THE PORTION OF THE BOUNDARY DRIFTING ACROSS THE LOWER OH..TN..LOWER MS VALLEYS THU INTO FRI BUT WAS STILL SOUTH OF ITS FRONTAL POSITION FROM THE 09/00Z RUN. THE 00Z RUN OF THE GFS BACKED AWAY FROM ITS PREVIOUS IDEA OF LIFTING THE UPPER LOW AND ASSOCIATED SURFACE LOW WEST ACROSS THE RIO GRANDE THROUGH THE DAY ON THURSDAY...AND WAS CLOSER TO THE 00Z NAM. ONE OF THE CONCERNS ABOUT THE PREVIOUS RUN OF THE ECMWF WAS ITS WESTERN/NORTHERN TRAJECTORY EARLY IN THE PERIOD. THE 10/00Z RUN OF THE ECMWF WAS SOUTH OF ITS PREVIOUS RUN BUT REMAINED WEST OF THE OTHER MODELS. GIVEN THAT...AM A BIT RELUCTANT TO INCLUDE IT INTO THE MODEL PREFERENCES AT THIS POINT. BY THE TIME THE DAY 3 PERIOD DRAWS TO A CLOSE AT 13/12Z...THE MODELS TENDED TO AGREE THAT THE TX LOW SHOULD HAVE FILLED AND LIFTED NORTH WITH AN OPEN WAVE OVER PARTS OF MO/AR WITH A NEGATIVE TILT ORIENTATION. THE GFS MAY BE A TAD FLAT HERE BY FH84 BUT WILL KEEP IT IN THE MIX THROUGHOUT THE 3 DAY PERIOD. REFER TO THE QPFPFD FOR FURTHER DETAILS CONCERNING QPF DIFFERENCES AND WPC'S PREFERRED SOLUTION. ...UPPER TROUGH/SURFACE LOW APPROACHING THE WEST COAST ON FRI... PREFERENCE: A GFS/ECMWF COMPROMISE (SIMILAR TO THE UKMET) CONFIDENCE: BELOW AVERAGE THE IDEA OF A SPLITTING TROUGH WHICH THE MODELS BEGAN DURING THE 09/12Z CYCLE WAS CONTINUED BY THE 00Z RUNS OF THE NCEP MODELS. THE UKMET IS IN THE GFS CAMP WITH RESPECT TO THE SURFACE LOW OVER THE ERN NOPAC...BUT OPENS UP THE FEATURE A LITTLE SOONER THAN THE GFS AND BECOMES A BIT FASTER. THE NAM LOOKED TOO SLOW FROM THE START...WHILE THE 09/12Z ECMWF AND THE EC ENSEMBLES TENDED TO GIVE MORE WEIGHT TO THE GFS/UKMET IDEA. WHILE THE TRENDS WOULD SUPPORT A MORE ECMWF-LIKE SOLUTION...CONFIDENCE IS ALSO LIMITED BY THE LACK OF RUN-TO-RUN CONSISTENCIES AND THE FACT THAT THE SYSTEM IS CURRENTLY CENTERED WELL OUT OVER THE NORTHERN PACIFIC. GIVEN THE UNCERTAINTY...RECOMMEND A COMPROMISE BETWEEN THE GFS AND THE ECMWF...SIMILAR TO THE UKMET. ...UPPER LEVEL SHORTWAVE/SURFACE FRONT MOVING ACROSS THE NORTHWESTERN U.S. TODAY THROUGH FRIDAY... ...PACIFIC COLD FRONT/ONSHORE FLOW IMPACTING THE WEST COAST BY EARLY SATURDAY... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE OVERALL...MODELS DID NOT SHOW ANY LARGE SCALE DIFFERENCES WITH THESE FEATURES. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN