MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1228 PM EDT THU JUL 14 2016 VALID JUL 14/1200 UTC THRU JUL 18/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z MODEL EVALUATION INCLUDING FINAL PREFERENCES AND FORECAST CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CLOSED MID LEVEL LOW TRACKING FROM THE UPPER MS VALLEY INTO ONTARIO THU AND COLD FRONT MOVING INTO NORTHEAST AND MID ATLANTIC THU-FRI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: OPERATIONAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE LITTLE CHANGE WITH EITHER 12Z NCEP MODEL TOWARD PRIOR GUIDANCE CONSENSUS WITH RESPECT TO THE UPPER LOW THAT WILL RAPIDLY SHEAR INTO CONFLUENT SWLY FLOW IN THE NORTHEAST AS WELL AS THE ASSOCIATED SURFACE FRONT CROSSING THE NORTHEAST/N MID-ATLANTIC THRU FRIDAY. OPERATIONAL MODEL BLEND AT ABOVE AVERAGE CONFIDENCE REMAINS PREFERENCE. SHORT WAVE CROSSING THE BASE OF LARGER SCALE TROF IN THE UPPER GREAT LAKES FRI/NEW ENGLAND BY SAT WITH ASSOCIATED FRONTAL ZONE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: OPERATIONAL MODEL BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE LITTLE CHANGE SEEN WITH THE 12Z ITERATIONS OF THE NAM/GFS WITH RESPECT TO THE MAIN SHORTWAVE TRACKING ACROSS THE GREAT LAKES FRI INTO NEW ENGLAND SAT. THE 12Z GFS REMAINS A BIT DEEPER/AMPLIFIED COMPARED TO THE OVERALL CLUSTER AT 5H BUT IT REMAINS SIMILARLY TIMED WITH THE SECONDARY FRONT/SURFACE TROF AS IT CROSSES ACROSS THE GREAT LAKES FRIDAY INTO THE NORTHEAST SAT. EVEN THOUGH THERE REMAIN THE DIFFERENCES ABOVE 7H IN AMPLITUDE BY THE GFS...ITS EFFECTS ARE MINOR ENOUGH TO KEEP AN OPERATIONAL MODEL BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE. SHORTWAVE SHED FROM THE WESTERN CLOSED LOW CROSSING THE NORTHERN TIER INTO GREAT LAKES SUN TO SUN EVENING ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-UKMET BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE SUBTLE SHORTWAVE ENERGY IS SHED AROUND THE CLOSED LOW IN THE NORTHERN ROCKIES SAT AFTERNOON SUPPORTING LEE CYCLOGENESIS WITH SAT WITH FAIRLY GOOD CONSENSUS IN PLACEMENT. THE WAVE BEGINS TO AMPLIFY ACROSS THE NORTHERN TIER OF THE US WITH INCREASED SUPPORT/INFLUENCE OF A STRONGER/DIGGING CANADIAN TROF. ONLY THE 00Z UKMET IS OUT OF PHASE FROM FAIRLY STRONG CONSENSUS HAVING AMPLIFIED THE NORTHERN STREAM TROF INTO THE DAKOTAS SUPPORTING A WEAK SURFACE WAVE ALONG THE EASTWARD PROGRESSING FRONTAL ZONE ON SUNDAY. AS SUCH WILL FAVOR A NON-UKMET BLEND AT SLIGHTLY ABOVE AVERAGE CONFIDENCE. THERE REMAINS SOME DIFFERENCES IN MOISTURE/INSTABILITY PLACEMENT ACROSS THE NORTHERN TIER/UPPER MS RIVER VALLEY SUNDAY THAT HAVE EFFECTS IN QPF...PLEASE SEE QPFPFD FOR ADDITIONAL MODEL PREFERENCES/DETAILS. LOW CROSSING THE PACIFIC NORTHWEST TODAY AND STALLING IN THE NORTHERN ROCKIES UNTIL SUN NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: OPERATIONAL MODEL BLEND CONFIDENCE: ABOVE AVERAGE BOTH THE 12Z NAM/GFS REMAIN TIGHTLY CLUSTERED TO THE PRIOR MODEL CONSENSUS REGARDING THE TIMING/STRENGTH OF A CLOSED 5H LOW THAT TRACKS FROM N VANCOUVER ISLAND ACROSS BC/WA BOARDER BEFORE STALLING OVER THE NORTHERN US ROCKIES. MODELS ALSO AGREE IN THE SLOW DEVOLUTION OF THE WAVE THROUGH SUNDAY TO SUPPORT AN OPERATIONAL MODEL BLEND AT ABOVE AVERAGE CONFIDENCE FOR THIS SYSTEM. AMPLIFYING SHORTWAVE OFF PACIFIC NW SUNDAY BECOMING A CLOSED LOW OFF WA/OR COAST SUN NIGHT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z GFS AND 00Z ECMWF/CMC BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE BY SAT NIGHT/SUN MORNING SHORTWAVE ENERGY OVER-TOPS THE STRONG PACIFIC RIDGE AND BEGINS TO AMPLIFY AND CARVE OUT A CLOSED LOW ALONG THE WA/OR COAST BY 00Z MONDAY. THE 12Z NAM REMAINS FAIRLY SLOW WITH THE INJECTION OF THE SHORTWAVE ENERGY OVER THE RIDGE AND CLOSES OFF A LOW WEST OF VANCOUVER ISLAND WITH SOME WEAK ENERGY IN THE REFORMATION OF THE BASE OF THE TROF OFF OR; THIS IS WELL OUT OF PHASE WITH THE REST OF THE GUIDANCE. THE 00Z UKMET APPEARS COMPARABLE TO THE REST OF THE SUITE IN PLACEMENT BUT IS QUITE FAST IN DEVELOPING A STRONGER/CONCENTRIC VORT CENTER OFF WA EARLY SUNDAY AND REMAINS OUT OF PLACE COMPARED TOWARD STRONGER EVOLUTION OF THE LOW SEEN WITH AGREEMENT IN THE 12Z GFS AND 00Z CMC/ECMWF AS WELL AS ALL THREE'S ENSEMBLE MEANS AND SPREAD. AS SUCH HAVE SLIGHTLY ABOVE AVERAGE CONFIDENCE IN A 12Z GFS/00Z ECMWF/00Z CMC BLEND AS PREFERENCE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GALLINA