MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 244 PM EDT FRI MAR 25 2016 VALID MAR 25/1200 UTC THRU MAR 29/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC AND ECMWF ...WEAKENING TROUGH OVER GREAT LAKES/NEW ENGLAND... ...EXITING SURFACE LOW/COLD FRONT CLEARING EAST COAST... PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE THE MODELS ARE IN GOOD AGREEMENT WITH THE MASS FIELD DETAILS OF THIS SYSTEM...SO WILL PREFER A GENERAL MODEL BLEND. ...SHORTWAVE ENTERING NORTHERN HIGH PLAINS... ...WEAKENING/PHASING WITH NORTHERN STREAM KICKER OVER UPPER MIDWEST... ...ASSOCIATED SURFACE LOW LIFTING ACROSS GREAT LAKES BY SUN... PREFERENCE: 12Z ECMWF CONFIDENCE: SLIGHTLY BELOW AVERAGE THE LEADING SMALL SHORTWAVE FEATURE EJECTING ACROSS THE NORTHERN PLAINS WILL SUPPORT A SURFACE LOW WITH AN INVERTED TROUGH EXTENDING NORTHEAST ACROSS SOUTH-CENTRAL CANADA THAT WILL BEGIN TO HAVE FURTHER INTERACTIONS WITH OTHER FEATURES ACROSS THE UPPER MIDWEST...INCLUDING A SHORTWAVE THAT DEVELOPS OUT OF CO/NM EARLY SAT WITH A SURFACE REFLECTION AS WELL BOTH MELDING AND LIFTING NORTHEAST OVER THE WESTERN GREAT LAKES BY SUN. ADDITIONAL NORTHERN STREAM ENERGY ALOFT WILL DESCEND OUT OF CANADA AND AMPLIFY IN THE CENTRAL PLAINS IMMEDIATELY IN BEHIND THE LEAD ENERGY...LEADING THE WAY FOR A MORE CONSOLIDATED UPPER TROUGH AND SURFACE LOW THAT WILL MOVE ACROSS THE GREAT LAKES REGION SUN. THE 12Z GFS BECOMES A BIT MORE AMPLIFIED WITH THE CONSOLIDATION OF THIS ENERGY AND WITH A SOMEWHAT DEEPER SURFACE WAVE CROSSING THE UPPER MIDWEST AND GREAT LAKES REGION. THE 12Z UKMET LAGS THE MODEL CONSENSUS SOMEWHAT BY SUN...WITH THE 12Z NAM/12Z CMC AND 12Z ECMWF A BIT MORE PROGRESSIVE BY COMPARISON. WILL LEAN TOWARD THE 12Z ECMWF AT THIS POINT GIVEN THAT THIS MODEL GENERALLY REFLECTS THE MULTI-MODEL CONSENSUS AND HAS SUPPORT FROM THE 00Z ECENS MEAN. CONFIDENCE THOUGH REMAINS SOMEWHAT LIMITED. ...SECONDARY SHORTWAVE DROPPING THROUGH THE INTERMOUNTAIN WEST/SOUTHERN HIGH PLAINS... ...DEVELOPING SURFACE LOW OVER THE SOUTHERN HIGH PLAINS SUN... ...CONSOLIDATING LOW PRESSURE MOVING THROUGH THE OH VALLEY/NORTHEAST... PREFERENCE: 12Z ECMWF CONFIDENCE: BELOW AVERAGE ADDITIONAL SHORTWAVE ENERGY DIGGING SOUTHEAST INTO THE FOUR CORNERS REGION WILL EJECT OUT INTO THE SOUTHERN HIGH PLAINS BY LATE SAT AND WILL ALLOW AN AREA OF LOW PRESSURE TO DEVELOP ALONG THE SOUTHERN END OF A FRONTAL ZONE SETTLING SOUTHEAST ACROSS THE PLAINS AND MIDWEST. ALL OF THIS ENERGY WILL THEN TRANSLATE OFF TO THE NORTHEAST AND AT LEAST PARTIALLY PHASE WITH NORTHERN STREAM TROUGH CROSSING THE GREAT LAKES BY LATER SUN. ON MON...THE MODELS SHOW SURFACE LOW PRESSURE ORGANIZING AND DEEPENING OVER THE OH VALLEY AND THEN LIFTING ACROSS THE NORTHEAST BEFORE REDEVELOPING OFFSHORE NEW ENGLAND BY TUES. THE 12Z GFS REMAINS OUT OF TOLERANCE RELATIVE TO THE OTHER GUIDANCE IN SUGGESTING LOW PRESSURE REMAINING FOCUSED MUCH FARTHER NORTH SUN AND MON. THE 12Z UKMET IS THE SLOWEST SOLUTION AND IS SLOWER THAN THE 12Z GEFS MEAN AND 00Z ECENS MEAN. THE 12Z ECMWF HAS THE SUPPORT OF THE 12Z NAM AND 12Z CMC...AND ALSO THE 00Z ECENS MEAN. WILL AGAIN LEAN TOWARD THE ECMWF...BUT CONFIDENCE IS LIMITED GIVEN THE OVERALL MODEL SPREAD AS THE SYSTEM EVOLVES. ...UPPER TROUGH/FRONT APPROACHING THE PACIFIC NORTHWEST BY LATE SAT... ...DEEP CLOSED LOW DEVELOPING OVER THE WEST MON AND TUES... PREFERENCE: BLEND OF THE 12Z GFS AND 12Z ECMWF CONFIDENCE: ABOVE AVERAGE A PROGRESSIVE UPPER TROUGH AND ASSOCIATED FRONT ADVANCING THROUGH THE GULF OF AK WILL DIG SHARPLY SOUTHEASTWARD SAT AND SUN INTO THE PACIFIC NORTHWEST AS STRONG HEIGHT RISES/RIDGING DEVELOPS SOUTHEAST OF THE ALEUTIANS AND THEN MOVES INTO THE GULF OF AK THROUGH THE PERIOD. THE RIDGE AMPLIFICATION WILL LEAD TO DEVELOPMENT OF A ROBUST CLOSED LOW OVER THE WEST BY LATE MON AND TUES. THIS WILL RESULT IN A BROAD AND DEEPENING AREA OF LOW PRESSURE ACROSS MUCH OF THE INTERMOUNTAIN REGION BY THE END OF THE PERIOD. THE 12Z UKMET ELONGATES THE UPPER LOW OVER THE WEST A BIT MORE TO THE SOUTHWEST BY LATE MON...WITH THE REMAINING MODEL CLUSTERED A LITTLE FARTHER NORTH. THE BEST MODEL CLUSTERING TENDS TO FAVOR A GFS/ECMWF CONSENSUS...AND GIVEN STRONG GEFS MEAN/ECENS MEAN SUPPORT...A BLEND OF THE GFS AND ECMWF WILL BE PREFERRED. HOWEVER...IN GENERAL THE MASS FIELD SPREAD IS RATHER SMALL BOTH AT THE SURFACE AND ALOFT WITH NO STRONG OUTLIER SOLUTIONS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON