MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1259 AM EDT SUN JUN 07 2015 VALID JUN 07/0000 UTC THRU JUN 10/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. CYCLONE MOVING ACROSS THE NORTHERN PLAINS & SOUTHEAST CANADA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF 12Z ECMWF/12Z GEFS MEAN/12Z ECMWF ENSEMBLE MEAN CONFIDENCE: ABOVE AVERAGE BEFORE 9/12Z...AVERAGE AFTERWARD CONTINUED STRONG CLUSTERING OF THE SURFACE LOW AND LIMITED SPREAD EXISTS WITH THE EVOLUTION OF THIS SYSTEM ACROSS THE UPPER MIDWEST INTO SOUTHEAST CANADA. SLIGHT DIFFERENCES BEGIN TO EVOLVE MAINLY WITH THE INTERACTION OF THE KICKER WAVE DESCRIBED BELOW THUS INCREASING THE SPREAD OF THE DETERMINISTIC MODEL RUNS WITHIN THE LIMITED SPREAD OF ENSEMBLE MEMBERS. THE 00Z NAM APPEARS TO BE THE DEEPEST SOLUTION AT FIRST GLANCE BUT IS WELL WITHIN THE SPREAD. THE 00Z GFS SOLUTION FOR THIS WAVE IS HIGHLY TIED TO THE UPSTREAM KICKER MAKING IT FAST AND FURTHER EAST WITH THE TROF MAKING IT LESS FAVORABLE. THE 12Z ECMWF MAY HAVE A BIT OF GRIDSCALE FEEDBACK MAINLY ON TUESDAY AS IT PROVIDES A STRONGER SURFACE REFLECTION ACROSS NEW YORK. THE 12Z UKMET IS A BIT FAST WITH THE EASTWARD PROGRESSION OF THE TROF COMPARED TO THE CLUSTER. THE 12Z ECMWF REMAINS THE MOST CENTRAL TO THE ENSEMBLE SPREAD EVEN WITH THE MINOR FEEDBACK...AS SUCH IS IN THE PREFERRED BLEND WITH THE 12Z GEFS MEAN AND 12Z ECMWF ENSEMBLE MEAN. CONFIDENCE IS ABOVE AVERAGE BEFORE THE INTERACTION WITH THE UPSTREAM TROF...AND AVERAGE AFTER TUESDAY 09/12Z. KICKER WAVE WITH COLD FRONT ACROSS NORTHERN TIER ON TUES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF 00Z NAM/12Z ECMWF/12Z UKMET CONFIDENCE: AVERAGE AS ALLUDED TO IN PRIOR SECTION...ENERGY CURRENTLY EJECTING OUT OF THE GULF OF ALASKA IS FORECAST TO MOVE OVER THE RIDGE AND DEEPEN ACROSS NORTHERN SASKATCHEWAN. DEPENDING ON HOW CONSOLIDATED THE WAVE COMES OVER THE TOP OF THE RIDGE DETERMINES THE SPEED OF THE TROF WHICH IS STRONGEST/FASTEST WITH THE 00Z GFS AND SLOWEST WITH THE BROAD BUT STRONG 12Z CMC MAKING THE SURFACE REFLECTION A BIT STRONGER THAN OTHER GUIDANCE AND FURTHEST NORTH AND WEST. AT THIS TIME...A BLEND OF THE 00Z NAM/12Z ECMWF AND 12Z UKMET IS SUPPORTED BY NUMEROUS 12Z GEFS AND 12Z ECMWF ENSEMBLE MEMBERS...AND AS SUCH IS THE PREFERENCE WITH AVERAGE CONFIDENCE. SHEARING OUT ENERGY IN THE GREAT BASIN TROPICAL CYCLONE BLANCA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: CLOSEST TO BLEND OF 00Z GFS/12Z ECMWF SOLUTIONS CONFIDENCE: SEE NHC ADVISORIES FOR FURTHER DETAILS THE 00Z NAM/GFS ALONG WITH 12Z UKMET/ECMWF/CMC ARE IN VERY GOOD AGREEMENT WITH THE EVOLUTION OF THE ENERGY SHEARING OUT ACROSS THE GREAT BASIN...SO ONLY DIFFERENCES ARE WITH APPROACH OF ENERGY AND MOISTURE WITH TROPICAL CYCLONE BLANCA...PLEASE SEE NHC DISCUSSIONS/ADVISORIES FOR FURTHER DETAILS. CLOSED CYCLONE OFFSHORE OF SOUTHERN CALIFORNIA TROUGHING DEVELOPING IN WEST BY DAY 3 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: NON-CMC BLEND CONFIDENCE: ABOVE AVERAGE GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE EVOLUTION OF THE BASE OF THE TROF OVER CALIFORNIA MERGING WITH ENERGY NEAR 29N131W . EVENTUALLY THE TROF DRIFTS NORTH AND EAST BACK TOWARD THE CALIFORNIA COAST BY TUES NIGHT/WED MORNING WHILE SIMULTANEOUSLY STARTING TO PHASE/MERGE WITH A SHORTWAVE ENTERING THE PACIFIC NORTHWEST ON DAY 3. MOST GUIDANCE IS WITHIN A FAIRLY STRONG AGREEMENT/SMALL SPREAD FOR DAY 3...ONLY THE 12 CMC REMAINS STRONGER AND FURTHER SOUTH WITH BOTH THE PACIFIC NORTHWEST SHORTWAVE AND THE CLOSED LOW AT THE BASE OF THE LARGER SCALE TROF. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GALLINA