MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 239 AM EDT MON APR 28 2014 VALID APR 28/0000 UTC THRU MAY 01/1200 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. ...DEPARTING CLOSED LOW EXITING INTO THE CANADIAN MARITIMES... FINAL PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: HIGH CURRENT WATER VAPOR IMAGERY SHOWED A CLOSED LOW SPINNING OFF THE COAST OF NOVA SCOTIA WITH THE SYSTEM CONTINUING TO MIGRATE FURTHER INTO THE CANADIAN MARITIMES. IN ITS WAKE...HEIGHTS SHOULD BEGIN TO RISE ALONG THE EASTERN U.S. AHEAD OF THE POWERFUL SYSTEM AFFECTING THE CENTER OF THE COUNTRY. GENERALLY THE MODELS ARE IN REASONABLE AGREEMENT WITH ONE ANOTHER TO AFFORD A GENERAL MODEL COMPROMISE HERE. ...POWERFUL MID-LATITUDE CYCLONE SLOWLY LIFTING FROM THE CENTRAL PLAINS INTO THE GREAT LAKES... FINAL/ PREFERENCE: THROUGH 60 HOURS: BLEND OF THE 00Z ECMWF/CMC...THEREAFTER: BLEND OF THE 00Z ECMWF/12Z ECMWF ENSEMBLE MEAN FORECAST CONFIDENCE: AVERAGE...THEN BECOMING SLIGHTLY BELOW AVERAGE AN ANOMALOUS CLOSED LOW SWIRLING ACROSS THE CENTRAL PLAINS HAS ALREADY MADE QUITE THE HEADLINES WITH THE WIDESPREAD SEVERE WEATHER/HEAVY RAINFALL...ALONG WITH SNOW ON THE BACKSIDE OF THE CYCLONE. THE UPPER LOW WILL EVER SO SLOWLY WEAKEN AS IT LIFTS TOWARD THE NORTH AND EAST INTO THE MIDDLE MS VALLEY BY EARLY TUESDAY MORNING. ITS FORWARD PROGRESS SHOULD CONTINUE TO BE THWARTED BY THE BLOCKING RIDGE DOWNSTREAM. AT THIS POINT THE 00Z NAM LOOKS TO BE TOO QUICK EJECTING THE VORTEX TOWARD THE EAST WITH SLOWER SOLUTIONS BEING PREFERRED GIVEN THE SYSTEM OF INTEREST IS A CUT-OFF LOW. BY WEDNESDAY MORNING...THE 00Z UKMET IS AWAY FROM THE CONSENSUS WITH ENERGY HANGING BACK ON THE SOUTHWESTERN FRINGE OF THE VORTEX ACROSS THE FOUR CORNERS REGION. THROUGH 30/1200Z...THE 00Z ECMWF/CMC ARE FAIRLY CLOSE TO ONE ANOTHER WHICH ALSO AGREE WITH THE ENSEMBLE MEANS. THEREAFTER...THE 00Z/12Z CMC ARE QUICKER TO ACCELERATE THE SOUTHWESTERN FRINGE OF THE SYSTEM WHICH DISAGREES WITH ENSEMBLE MEANS AND AVAILABLE SPAGHETTI PLOTS. FROM 60 HOURS ONWARD WILL FAVOR A COMBINATION OF THE 00Z ECMWF/12Z ECMWF ENSEMBLE MEAN. www.wpc.ncep.noaa.gov/html/model2.shtml... RUBIN-OSTER