MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 106 AM EDT WED JUN 10 2015 VALID JUN 10/0000 UTC THRU JUN 13/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT RANGE FORECASTS. WEAKENING EASTERN CANADA/NEW ENGLAND TROF - THURS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF OPERATIONAL MODELS CONFIDENCE: ABOVE AVERAGE VERY TIGHT CLUSTERING AND SPREAD ASSOCIATED WITH THE EXITING SURFACE LOW OVER NEW ENGLAND AND LINGERING SURFACE TROF ALONG THE EASTERN SEABOARD WITH VERY LITTLE SYNOPTIC DIFFERENCES NOTICED. MINOR MESOSCALE IN THE WEAK FLOW ACROSS THE DEEP SOUTH SHOULD BE THE LARGEST DISCREPANCIES... SO A GENERAL MODEL BLEND IS ACCEPTABLE WITH THIS FEATURE AT ABOVE AVERAGE CONFIDENCE. KICKER WAVE MOVING ACROSS GREAT LAKES INTO SOUTHEAST CANADA/ NEW ENGLAND BY FRIDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF OPERATIONAL MODELS CONFIDENCE: ABOVE AVERAGE THE SOLUTIONS OF THE OPERATIONAL MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE LOCATION AND STRENGTH OF THE SURFACE LOW MOVING ACROSS ONTARIO INTO NEW BRUNSWICK BY FRIDAY ALONG WITH THE FRONTAL ZONE. A SLIGHT SPREAD STARTS TO LINGER AT THE BASE OF THE SURFACE TROF ACROSS THE MID-ATLANTIC ON FRIDAY INTO SATURDAY MAINLY DUE TO THE EASTWARD PROGRESS OF THE NEXT SYSTEM... GIVEN THIS IS MINOR AND LIKELY RELATED MORE TO THE INTERACTION UPSTREAM SYSTEM... THE OVERALL EVOLUTION CAN BE HANDLED WITH A BLEND OF THE OPERATIONAL MODELS AT ABOVE AVERAGE CONFIDENCE. REMNANTS OF BLANCA PHASING WITH NORTHERN STREAM TROF ACROSS CENTRAL PLAINS/GREAT LAKES WITH SURFACE LEE-CYCLOGENESIS IN COLORADO MOVING ACROSS GREAT LAKES INTO NEW ENGLAND THURS-SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF 00Z GFS/NAM 12Z ECMWF ENSEMBLE MEAN CONFIDENCE: SLIGHTLY ABOVE AVERAGE SHORTWAVE ENERGY FROM REMNANT OF BLANCA TREK NORTHEAST ACROSS THE FOUR CORNERS EJECTING INTO THE PLAINS WED NIGHT-THURS. VERY GOOD AGREEMENT EXISTS WITH THE 00Z GFS/NAM CONTINUING A FASTER TREND SEEN WITH THE ECMWF WITH BOTH MODELS LOOKING VERY AGREEABLE WITH THE 12Z ECMWF MEAN. GIVEN BETTER AGREEMENT THE SUBTLE DIFFERENCES WITH THE 12Z OPERATIONAL ECMWF BECOME A BIT MORE GLARING... BEING FASTER/FURTHER EAST AND BY SAT BECOMING WEAKER WITH THE SURFACE LOW/NEARLY ABSORBED INTO THE NORTHERN STREAM ALOFT. STILL GIVEN THAT THE ECMWF HAS BEEN LEADING THIS TREND IT CANNOT BE DISCOUNTED. AS SUCH...THE 00Z GFS/NAM/12Z ECMWF ENSEMBLE MEAN IS THE PREFERRED BLEND BUT SLIGHTLY ABOVE AVERAGE CONFIDENCE AS IT DOES NOT FULLY ENCASE THE 12Z ECWMF SOLUTION. CUT-OFF LOW SOUTHWEST CALIFORNIA COAST MOVES EAST EVENTUALLY EJECTING INTO THE PLAINS 00Z SAT. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: BLEND OF 00Z NAM/GFS/12Z ECMWF CONFIDENCE: SLIGHTLY ABOVE AVERAGE VERY GOOD AGREEMENT OF THE EVOLUTION OF THE CUT-OFF LOW AS IT TREKS ACROSS THE SOUTHWEST BETWEEN THE 00Z NAM/GFS/12Z ECMWF SUPPORTED BY THE 12Z GEFS MEAN/12Z ENSEMBLE MEANS. THE 12Z CMC A BIT TOO DEEP PER ITS BIAS AND THE 12Z UKMET EJECTING MUCH TOO STRONG AND FAST. A BLEND OF THE 00Z NAM/GFS AND 12Z ECMWF IS PREFERRED. HOWEVER...THERE MAY BE SOME WEAK CONVECTIVE FEEDBACK AT THE END OF THE PERIOD (06Z SATURDAY) LEADING TO A STRONGER/CLOSED LOW ACROSS OK. THOUGH POSSIBLE...EXACT LOCATION OF MESOSCALE INFLUENCES FAVORS THE INCLUSION OF THE ENSEMBLE MEANS ON DAY 3. THIS SHOULD PROVIDE STABILITY AS WELL AS SLIGHTLY ABOVE AVERAGE CONFIDENCE WITH ITS ADDITION. TROUGH ENTERING THE PACIFIC NORTHWEST FRI-SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PRELIMINARY PREFERENCE: 12Z ECMWF AND 12Z ECMWF ENSEMBLE MEAN CONFIDENCE: SLIGHTLY BELOW AVERAGE THE EVOLUTION OF THE ALASKAN PENINSULA TROF AS IT DEEPENS INTO THE PACIFIC NORTHWEST IS IN FAIRLY GOOD AGREEMENT WITH THE OPERATIONAL AND ENSEMBLE GUIDANCE SUITE THROUGH DAY 1. THIS AGREEMENT STARTS TO BREAKDOWN ON FRIDAY WITH THE 12Z UKMET BREAKING AWAY FASTER TOWARD THE EAST AND THE 12Z CMC BECOMING A BIT DEEP IN LINE WITH THEIR BIASES. THE 00Z NAM AND GFS ALONG WITH THEIR ENSEMBLE SUITES REMAIN SLOWER THAN THE 12Z ECMWF/ECMWF ENSEMBLE MEAN BY THE END OF THE PERIOD. THE ECWMF ALSO IS BROADER THAN THE AMERICAN MODELS. ALOFT THE 12Z CMC GETS IN BETTER AGREEMENT WITH 12Z ECMWF BUT THE SURFACE REFLECTION IS MUCH TOO STRONG...SOUTH AND WEST...ELIMINATING IT FROM SOME POTENTIAL IN THE BLEND. THE CONFIDENCE IN THE BLEND OF THE 12Z ECMWF AND THE 12Z ECMWF ENSEMBLE MEAN IS LOWERED TO SLIGHTLY BELOW AVERAGE AS THE SPREAD IN THE THE SURFACE LOW CLUSTER AND SPAGHETTI PLOTS IN THE MID-LEVELS IS MUCH HIGHER THAN THE PACKING OF THE LESS PREFERRED (GIVEN ITS SLOWER SOLUTION) 12Z GEFS MEAN. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GALLINA