MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1251 AM EDT FRI JUN 17 2016 VALID JUN 17/0000 UTC THRU JUN 20/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS ...SHORTWAVE/SURFACE LOW TRACKING TROUGH THE MID-ATLANTIC THROUGH FRI... ...SURFACE LOW REDEVELOPMENT/DEEPENING EAST OF THE MID-ATLANTIC SUN/MON... PREFERENCE: BLEND OF THE 12Z UKMET/12Z CMC AND 12Z ECMWF CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE THE MODELS ARE IN GOOD AGREEMENT OVER THE NEXT COUPLE OF DAYS IN TAKING A SHORTWAVE AND ASSOCIATED SURFACE LOW SOUTHEAST THROUGH THE MID-ATLANTIC COASTAL PLAIN AND THEN OFFSHORE. THE 00Z GFS DOES AGAIN APPEAR TO BE TOO WEAK WITH THE ENERGY AND SURFACE LOW AS IT EXITS THE MID-ATLANTIC REGION BY LATE FRI. ON SUN...ALL OF THE MODELS SHOW THIS SURFACE LOW PUSHING A BIT FARTHER OFFSHORE...BUT THE MODELS ALL AGREE IN DROPPING SOME NORTHERN STREAM SHORTWAVE ENERGY SOUTHEAST THROUGH NEW ENGLAND AND THEN SOUTH OFFSHORE THE EAST COAST WHERE IT IS EXPECTED TO CAPTURE THE SURFACE LOW. THE RESULT WILL BE A STRONGER PHASED MID LEVEL LOW CENTER WITH A DEEPENING SURFACE LOW THAT BY MON IS EXPECTED TO DO A CYCLONIC LOOP EAST OF THE MID-ATLANTIC COAST. THE 00Z GFS IS THE WEAKEST SOLUTION WITH THE 12Z ECMWF THE STRONGEST. THE 00Z NAM IS CLOSE TO THE 00Z GFS WITH THE LOW EVOLUTION AND IS ONLY A TAD STRONGER. MEANWHILE...THE 12Z UKMET AND 12Z CMC TEND TO FAVOR A DEEPER LOW BY SUN AND MON...BUT NOT QUITE TO THE EXTENT OF THE 12Z ECMWF. THERE IS RATHER CONSIDERABLE SPREAD WITH THE ECENS AND GEFS MEMBERS ON THE EVOLUTION AND DEPTH...WITH THE ECENS MEMBERS GENERALLY STRONGER AND THE GEFS MEMBERS WEAKER. WILL PREFER A NON-GFS CONSENSUS...WEIGHTED TOWARD A CONSENSUS OF THE NON-NCEP GUIDANCE FOR THE TIME BEING. ...COLD FRONT CROSSING THE DAKOTAS THROUGH FRI... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THIS FEATURE...AND SO A GENERAL MODEL COMPROMISE WILL BE PREFERRED. ...LOW PRESSURE OVER THE CENTRAL/SOUTHERN HIGH PLAINS FRI/SAT... PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THERE ARE SOME MINOR NORTH/SOUTH DIFFERENCES WITH THE POSITION OF A LEE LOW THAT FOCUSES NEAR THE CO/KS BORDER AND THEN GRADUALLY SETTLES SOUTH THROUGH THE OK/TX PANHANDLES. WILL PREFER A GENERAL MODEL COMPROMISE TO RESOLVE THESE DIFFERENCES. ...CLOSED LOW OVER THE PACIFIC NORTHWEST THROUGH SAT... ...SURFACE LOW/FRONT EJECTING ACROSS THE NORTHERN PLAINS SUN/MON... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: AVERAGE AN UPPER LOW WILL CROSS THE PACIFIC NORTHWEST THIS WEAKEN AND THEN BEGIN TO SHEAR OUT BY SUN ACROSS SOUTHERN BRITISH COLUMBIA AND SOUTHERN ALBERTA. THEREAFTER...THE ENERGY WILL SHEAR EAST ALONG THE U.S/CANADIAN BORDER AND WILL DRIVE A WAVE OF LOW PRESSURE AND ASSOCIATED COLD FRONT EAST ACROSS THE NORTHERN PLAINS AND UPPER MS VALLEY. THE LOW WILL THEN BE ABSORBED BY A DEEPER TROUGH OVER CENTRAL CANADA BY MON. THE 12Z UKMET IS A FASTER AND SOMEWHAT DEEPER OUTLIER SOLUTION WITH THE EVOLUTION OF THIS SYSTEM. THE 12Z CMC GRADUALLY BECOMES THE SLOWEST SOLUTION. THE 00Z NAM/00Z GFS AND 12Z ECMWF ALL SPLIT THE DIFFERENCE...BUT THE 00Z NAM EVENTUALLY APPEARS TO BE TOO WEAK WITH ITS SURFACE LOW. WILL PREFER A BLEND OF THE GFS AND ECMWF AT THIS POINT. ...CLOSED LOW OFF THE WEST COAST BY SUN/MON... PREFERENCE: BLEND OF THE 00Z GFS AND 12Z ECMWF CONFIDENCE: ABOVE AVERAGE THE MODELS ALL DEVELOP ANOTHER CLOSED LOW OFFSHORE THE WEST COAST BY SUN AND MON AS ADDITIONAL SHORTWAVE ENERGY DIGS SOUTH OFFSHORE BRITISH COLUMBIA. THE 00Z GFS AND 12Z ECMWF CLUSTER OVERALL RATHER WELL WITH EACH OTHER...AND A BLEND OF THESE SOLUTIONS WILL BE PREFERRED. THE REMAINING GUIDANCE IS GENERALLY CLOSE TO THE GFS/ECMWF CLUSTER. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... ORRISON