MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 249 AM EDT THU MAY 07 2015 VALID MAY 07/0000 UTC THRU MAY 10/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...00Z MODEL MASS FIELD EVALUATION ALONG WITH FINAL PREFERENCES... ...LOW PRESSURE DEEPENING OFF THE SOUTHEAST COAST... MODELS CONTINUE TO COME INTO BETTER AGREEMENT WITH DEEPENING A SURFACE LOW OFF THE SOUTHEAST COAST LATE THIS WEEK AND TRACKING IT NORTHWEST/WESTWARD TOWARDS THE CAROLINA COAST THIS WEEKEND. THE 00Z NAM/GFS MADE MINIMAL ADJUSTMENTS FROM THEIR 18Z RUNS AND STILL FIT IN WELL WITHIN THE CURRENT MODEL SPREAD IN TERMS OF TRACK AND DEPTH. THE 00Z ECMWF/UKMET/CMC SHOW MINOR PLACEMENT DIFFERENCES WITH THE UKMET TAKING THE STORM INLAND ACROSS THE NC/SC BORDER SAT NIGHT. THE LATEST TROPICAL WEATHER OUTLOOK FROM THE NATIONAL HURRICANE CENTER HAS A 70 PERCENT CHANCE OF THIS SYSTEM BECOMING A TROPICAL OR SUBTROPICAL STORM LATER TODAY OR FRIDAY. PLEASE REFER TO PRODUCTS FROM THE NATIONAL HURRICANE CENTER FOR THE LATEST INFORMATION ON THIS SYSTEM. ...SHORTWAVE LIFTING OUT OF THE UPPER MIDWEST/COLD FRONT CROSSING THE GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY... PREFERENCE: 12Z/00Z ECMWF BLEND CONFIDENCE: AVERAGE DETERMINISTIC GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH LIFTING A SHORTWAVE AND ASSOCIATED SURFACE LOW OUT OF THE UPPER MIDWEST ON THURSDAY AND THEN PRESSING A TRAILING COLD FRONT EAST/SOUTHWARD THROUGH THE UPPER GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY FRIDAY AND SATURDAY. THE MOST LARGE SCALE DIFFERENCE IS WITH A POSSIBLE SURFACE WAVE ALONG THE BOUNDARY THAT COULD TRACK NORTHWARD THROUGH THE MIDDLE MISSISSIPPI VALLEY FRIDAY AFTERNOON. THE 12Z UKMET/CMC...AND TO A LESSER EXTENT...THE 12Z ECMWF ARE THE MOST ROBUST WITH THIS FEATURE...WHILE BOTH THE 00Z NAM/GFS ARE LESS AGGRESSIVE WITH THE IDEA. THE 00Z UKMET/CMC HAVE TRENDED WEAKER WITH THIS LOW...WHILE MINIMAL CHANGE IN THE 00Z ECMWF. GIVEN THE SURFACE WAVE IN THE GFS IS LOCATED SOUTHEASTWARD OF THE REMAINING MODEL CLUSTERING BY SAT MORNING...AND THE RELATIVE GOOD CONTINUITY OF THE ECMWF...WILL LEAN TOWARD THE BETTER POSITION CLUSTERING AND TOWARD THE WEAKER TREND CLOSE TO THE PAST TWO RUNS OF THE ECMWF. FOR MORE DETAILED INFORMATION WITH RESPECT TO PRECIPITATION...PLEASE REFER TO THE QPFPFD. ...CLOSED LOW EDGING OUT OF THE SOUTHWEST/CYCLOGENESIS IN THE SOUTHERN HIGH PLAINS... PREFERENCE: NON 00Z NAM COMPROMISE CONFIDENCE: ABOVE AVERAGE A DEEP VORTEX WILL DROP DOWN THE WESTERN U.S. ON THURSDAY BEFORE SLOWLY EDGING EAST OUT OF THE SOUTHWEST ON FRIDAY. OUTSIDE OF THE 00Z NAM...WHICH DOES NOT HOLD ONTO A CLOSED LOW INTO THE PLAINS THROUGH SUN MORNING...MODELS ARE IN GOOD AGREEMENT WITH THE LARGE SCALE EVOLUTION OF THIS FEATURE...AND SIMILAR WITH SPINNING UP A SURFACE CYCLONE IN THE SOUTHERN HIGH PLAINS AS HEIGHT FALLS EJECT OUT EAST OF THE ROCKIES ON SATURDAY. FOR PRECIPITATION RELATED IMPACTS...PLEASE REFER TO THE QPFPFD. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GERHARDT/OTTO