MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 301 AM EDT WED JUL 09 2014 VALID JUL 09/0000 UTC THRU JUL 12/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 00Z CMC/UKMET/ECMWF ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ...UPPER TROF ANCHORING NORTHEASTERN NORTH AMERICA... ...SURFACE BOUNDARY EXITING THE NORTHEASTERN U.S... FINAL PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE A DEEP AND ANOMALOUS TROF WILL BE FEATURED ACROSS NORTHEASTERN NORTH AMERICA FOR MUCH OF THE WEEK. A SERIES OF SHORTWAVES ARE FORECAST TO TRAVERSE ABOUT THE BASE OF TROF WITH THE MEAN NEGATIVE ANOMALY SHIFTING EASTWARD IN TIME. THROUGH 48 HOURS...11/0000Z...THE MODELS ARE IN REASONABLE AGREEMENT WITH THE FORECAST EVOLUTION. FORTUNATELY THE 00Z CMC HAS SHIFTED TOWARD THE COAST WITH THE SURFACE FRONTAL PLACEMENT WHICH BRINGS IT MORE IN LINE WITH THE OTHER GUIDANCE. THE OVERALL 500-MB HEIGHT PATTERN OVER THE NORTHEASTERN U.S. IS NOT TERRIBLY DIFFERENT ACROSS THE BOARD WITH MORE OF THE UNCERTAINTY WITH THE CORE OF LOWER HEIGHTS UP IN QUEBEC. WITH THE 00Z CMC MAKING THE APPROPRIATE CHANGES OFFSHORE OF NEW ENGLAND...WILL FAVOR A GENERAL MODEL COMPROMISE HERE. ...BROAD UPPER TROF MOVING ACROSS WESTERN/CENTRAL CANADA... ...SHORTWAVE SLIDING THROUGH THE NORTHERN PLAINS/UPPER MIDWEST ON THURSDAY... FINAL PREFERENCE: BLEND OF THE 00Z GFS/ECMWF FORECAST CONFIDENCE: AVERAGE MODELS DEPICT A SYSTEM EVOLVING OUT OF THE GULF OF AK WITH HEIGHT FALLS SPREADING INLAND ACROSS WESTERN U.S. BY MID-WEEK. THE CORRIDOR OF STRONGEST HEIGHT FALLS APPEAR TO BE CONFINED TO CANADA WITH QUASI-ZONAL FLOW PREVAILING FROM THE PACIFIC NORTHWEST INTO THE NORTHERN PLAINS. MORE OF THE CONUS FOCUS WILL BE ON A SHORTWAVE SWINGING THROUGH THE NORTH-CENTRAL U.S. ON THURSDAY BEFORE MIGRATING INTO THE UPPER GREAT LAKES BY THE FOLLOWING DAY. AFTER REVIEWING THE 00Z GUIDANCE...THE FLATTER SOLUTIONS OF THE 12Z CMC/UKMET HAVE TRENDED TOWARD MORE AMPLIFICATION IN THE 00Z CYCLE. THIS HELPS BRING MOST OF THE DETERMINISTIC GUIDANCE MORE IN LINE WITH THE ENSEMBLE MEANS. THE PREFERENCE FROM EARLIER WILL BE MAINTAINED HOWEVER AS THEY STILL HANDLE THE NORTHERN STREAM BETTER. ...WEAK TROF OFFSHORE OF THE WEST COAST LATE IN THE PERIOD... FINAL PREFERENCE: BLEND OF THE 00Z GEFS/12Z ECMWF ENSEMBLE MEANS FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE TOWARD THE END OF THE WORK WEEK AND INTO THE EARLY PORTION OF THE UPCOMING WEEKEND...THE GUIDANCE SHOWS AN ELONGATED UPPER TROF SITTING JUST OFFSHORE OF THE WESTERN U.S. ALL OF THE 00Z GUIDANCE NOW SHOW TWO DISTINCT SHORTWAVE FEATURES ALTHOUGH EACH MODEL VARIES WITH THE PLACEMENT. THE 00Z NAM/GFS ARE FARTHER TOWARD THE EAST WHICH AGREES CLOSELY WITH THE 00Z GEFS/21Z SREF MEANS. MEANWHILE...ANOTHER CAMP SETS UP TOWARD THE WEST WHICH IS MORE IN LINE WITH THE 12Z ECMWF ENSEMBLE MEAN. AS THE MODELS CONTINUE TO WAVER WITH THEIR SOLUTIONS...WILL IT WOULD BE BEST TO BLEND THE ENSEMBLE MEANS UNTIL THE FINER DETAILS IRON THEMSELVES OUT. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RUBIN-OSTER