MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 151 AM EST FRI NOV 11 2016 VALID NOV 11/0000 UTC THRU NOV 14/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z EVALUATION OF MODEL GUIDANCE ALONG INCLUDING PREFERENCES AND FORECAST CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ TROUGH AND ASSOCIATED FRONTAL ZONE SWEEPING THROUGH THE GREAT LAKES/NORTHEASTERN U.S. THROUGH SAT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE MODEL CONSENSUS CONTINUES TO TIGHTEN WITH THE 5H TROF AND JET AXIS RAPIDLY CROSSING THE GREAT LAKES AND THROUGH NEW ENGLAND. ONLY MODEL DIFFERENCES CONTINUE TO BE THE HANDLING OF THE TAIL END OF THE TROF THAT SWEEPS SOUTHWARD ACROSS THE GREAT LAKES/OH VALLEY AND ITS REMAINING CONNECTION TO THE MAIN TROF THROUGH THE MID-ATLANTIC/CAROLINAS THROUGH SAT. GIVEN THE SPREAD/DIFFERENCES FOR THIS FEATURE...ADDED A SECTION BELOW TO DEFINE BETTER SPECIFICS FOR THAT FEATURE. OTHERWISE WILL FAVOR A GENERAL MODEL BLEND AT ABOVE AVERAGE CONFIDENCE ACROSS THE GREAT LAKES/NEW ENGLAND/MID-ATLANTIC. SOUTHWESTERN FLANK OF TROF CLOSING OFF NEAR MID-MS VALLEY SAT...LIFTING INTO OH/TN VALLEY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z GFS/CMC/ECMWF BLEND CONFIDENCE: BELOW AVERAGE DAY TO DAY ENSEMBLE COMPARISONS HAVE SHOWN A SLOW TRANSITION INCREASING CONVERGENCE TOWARD AN ANTICYCLONIC WAVE BREAKING SOLUTION ALONG THE SOUTHWEST FLANK OF THE DEEP TROF AS IT DESCENDS SOUTHWARD INTO THE MID-MS VALLEY/TN VALLEY BY SAT/SUN. THE CMC WAS FIRST TO SUGGEST THIS PATTERN 2 DAYS AGO AND SINCE THEN NUMEROUS ECENS MEMBERS HAVE TRANSITIONED WHILE GEFS MEMBERS WERE SLOWER BUT SHOWING THIS WAVE BREAK AND MUCH FURTHER WEST INTO KS. THE 00Z NAM CONTINUES TO BE SHALLOWER AND FASTER SHIFTING THE BASE OF THE TROF THROUGH THE EASTERN SOUTH/CAROLINAS RESULTING IN A COASTAL TROF BY SUN MORNING. THE 12Z UKMET HAS SHOWN SOME RUN TO RUN CONSISTENCY WITH A WEAK WAVE BREAK OVER THE PAST FEW DAYS BUT CLOSING OFF NEAR AL/GA. THE 00Z GFS HAS TRENDED A BIT WEAKER BUT STILL REMAINS WEST OF THE REMAINING CONSENSUS IN THE ENSEMBLE PLOT INCLUDING THE 12Z ECMWF/CMC SOLUTIONS. EVENTUALLY THE CLOSED UPPER LOW SYSTEM WILL ABSORB THE REMAINING SHORTWAVE ENERGY FROM THE WEAKENING OPEN WAVE EXITING MX AND WILL FEEL THE APPROACH OF NORTHERN STREAM KICKER WAVE AND SHIFT EASTWARD INTO THE OHIO/TN VALLEY WITH FAIRLY GOOD TIMING WITHIN THE GUIDANCE SUITE. THIS EVEN INCLUDES THE 00Z NAM AND 12Z UKMET WHILE WEAKER HAVING ONLY ENERGY FROM THE OPEN WAVE OUT OF MX/TX...LEAVING FAIRLY AGREEABLE PATTERN IN THE GUIDANCE BY MON ACROSS THE REGION WITH DIFFERENCE MAINLY IN STRENGTH OF THE WAVE. WILL KEEP WITH CONTINUITY PREFERENCE OF A BLEND OF THE 00Z GFS AND 12Z ECMWF/CMC...THOUGH CONFIDENCE REMAINS SLIGHTLY BELOW AVERAGE GIVEN THE REMAINING SPREAD IN STRENGTH/POSITION OF THE CLOSING OFF WAVE...THOUGH CONFIDENCE DOES INCREASE BY MONDAY AS THE TIMING OF THE WAVE IMPROVES INTO THE OH/TN VALLEY. 07Z UPDATE: THE 00Z UKMET SHIFTED A BIT FURTHER EAST MATCHING THE 00Z NAM AND AWAY FROM THE ENSEMBLE SOLUTION AND OVERALL TREND. HOWEVER...THE 00Z ECMWF TRENDED EASTWARD AS WELL LEADING TO RIDGING BETWEEN THE OPEN TROF OVER THE SOUTHERN PLAINS WHICH CONTINUES TO SHOW THE VERY LOW PREDICTABILITY OF THIS WAVE BREAK TIMING/STRENGTH. THE CMC CONTINUES TO SHOW THE MOST CONSISTENCY THOUGH WITH A LITTLE SHIFT TO THE EAST FROM THE 12Z RUN...IT MATCHES CLOSE TO THE PLACEMENT/STRENGTH OF THE 10TH/00Z RUN. WILL KEEP WITH THE ECMWF/GFS/CMC BLEND GIVEN OVERALL TREND TO THIS SOLUTION BUT CONFIDENCE IS FURTHER REDUCED GIVEN THE OVERALL SPREAD EXPANDING AND IS NOW BELOW AVERAGE. BROAD CUT-OFF LOW SPINNING OVER NORTHERN MX THE NEXT COUPLE OF DAYS DRIFTING BACK TOWARD TX AS AN OPEN WAVE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL BLEND UP TO 13/12Z 00Z GFS/NAM/UKMET AFTERWARD CONFIDENCE: ABOVE AVERAGE UP TO 13/12Z SLIGHTLY BELOW AVERAGE AFTERWARD GOES EAST WAVE SHOWS BROAD CUT-OFF LOW CENTERED JUST SW OF EL PASO TX WITH A BROADENING EASTERN EXTENT OF THE CIRCULATION AS SUBTROPICAL JET LIFTS NORTHWARD INTO THE LOW MS VALLEY. AS THE INNER CORE CONTINUES TO SLOWLY FILL AND TROF OUT OF THE NORTHERN STREAM DROPS SOUTH...ELONGATION OF THE WAVE TOWARD THE NORTHEAST WILL OCCUR AS THE REMAINING ENERGY LIFTS INTO TX/OK SAT. BY THIS POINT A GENERAL MODEL BLEND WILL SUFFICE WITH ABOVE AVERAGE CONFIDENCE. FURTHER MODEL DIFFERENCES ARE RELATED TO STRENGTH OF THE ANTICYCLONIC WAVE BREAK OVER THE MID-MS VALLEY. PLEASE SEE SECTION ABOVE FOR FURTHER DETAILS AND MODEL PREFERENCES AFTER SAT FOR ANYTHING REMAINING OF THIS SYSTEM. 07Z UPDATE: MODELS CONTINUE TO BE FAIRLY AGREEABLE WITH THE EARLY EVOLUTION AND TREND TOWARD LIFTING NORTHEAST AND OPENING UP...BUT WITH THE WAVE BREAKING FURTHER EAST FOR THE 00Z ECMWF/CMC THERE IS LESS INTERACTION/MERGING OF THESE FEATURES THROUGH THE MS RIVER VALLEY...WITH MILD RIDGING SEEN IN THE ECMWF MAKING IT SLOWER AND EXCESSIVE DIGGING UPSTREAM FROM AN OVERLY DEEP TROF IN THE CMC. THIS LEADS TO SOME CONCERN WITH THE INITIAL PREFERENCE/ENSEMBLE SPREAD INDICATING THIS MERGER OR SLIGHT EASTWARD SHIFT OF THE OVERALL TROF INTO THE TN/OH VALLEY. GIVEN THIS WILL FAVOR A SOLUTION MORE IN LINE WITH THE EARLIER PREFERENCE: GFS/NAM/UKMET BUT WITH REDUCED CONFIDENCE (SLIGHTLY BELOW AVERAGE). SHORTWAVE REACHING THE PACIFIC NORTHWEST COAST EARLY SAT AND TRACKING ACROSS THE NORTHERN TIER SUNDAY INTO MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON-CMC BLEND CONFIDENCE: AVERAGE AMPLIFIED STRONG WAVE SEEN IN GOES WV MOSAIC CONTINUES TO MARCH TOWARD THE PACIFIC NORTHWEST CROSSING 140W AT THIS TIME. THE MODELS ARE WELL GROUPED AND SHOW THE N-S ELONGATION OF THE LOW AS PRESENTED IN THE WV LOOP WITH EXCEPTION OF THE 12Z CMC WHICH SHOWS A DEEPER MORE CONSOLIDATED WAVE. THOUGH THE CMC MATCHES THE POSITION OF THE INNER CORE OF THE WAVE ON WV THE CONSOLIDATION LEADS TO SLIGHT SLOWER AND SOUTHWARD TRACK COMPARED TO BETTER MODEL CONSENSUS EVEN TRACKING THROUGH THE HIGHER TERRAIN OF THE ROCKIES...PRESENTING A SLOWER/DEEPER TROF CROSSING THE NORTHERN TIER INTO MONDAY. THE 00Z NAM ALSO INDICATES A MORE CONSOLIDATED WAVE ONCE LANDFALL IS REACHED ON SAT IN LINE WITH A KNOWN NEGATIVE BIAS. THE NAM THEN TRANSLATES THE DEEPER WAVE ACROSS THE ROCKIES/NORTHERN TIER THROUGH MONDAY THOUGH THIS DOES NOT SEEM TO NEGATIVELY MANIFEST WITH THE WAVE BELOW 7H INCLUDING THE SURFACE REFLECTION. LITTLE SIGNIFICANT CHANGE SEEN IN THE 00Z GFS STILL MATCHING WITH TIMING OF THE UKMET/ECMWF JUST A BIT WEAKER...ALLOWS FOR A NON-CMC BLEND THROUGH THE SHORT RANGE PERIOD BUT SUFFICIENT SPREAD REMAINING IN THE SUITE SUPPORTS ONLY AVERAGE CONFIDENCE IN THIS BLEND. 07Z UPDATE: LITTLE CHANGE OVERALL WITH THE UKMET/ECMWF EXCEPT FOR SLIGHTLY WEAKER SOLUTIONS TO THE SURFACE REFLECTION CROSSING SOUTHERN CANADA...WITH THE ECWMF NEARLY MATCHING THE 00Z GFS. THIS PROVIDES CONTINUED CONFIDENCE OVERALL. THE 00Z CMC CONTINUES TO BE DEEPER AT LANDFALL AND EVEN MORE SO CROSSING THE CENTRAL ROCKIES INTO THE PLAINS. AS SUCH WILL CONTINUE TO PREFER A NON-CMC BLEND. TIGHTLY PACKED ZONAL FLOW WITH EMBEDDED SHORTWAVES AFFECTING PACIFIC NORTHWEST SUN/MON ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 00Z NAM/ECMWF/CMC/GEFS BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE IN THE WAKE OF THE TROF/CLOSED LOW SATURDAY IN THE PACIFIC NORTHWEST... FLOW BECOMES VERY ZONAL BUT GIVEN A VERY STRONG UL FURTHER TO THE NORTH...THE HEIGHT PACKING THROUGH THE ZONAL FLOW REMAINS VERY TIGHT WITH EMBEDDED SHORTWAVE ENERGY RUNNING THROUGH IT. STRONG MODEL AGREEMENT EXISTS WITH A STREAM OF MOISTURE REACHING VANCOUVER ISLAND/NW WA BY SUNDAY MORNING. THE 00Z GFS HOWEVER BROKE FROM THIS STRONG CONSENSUS SUGGESTING A DEEPER WAVE TO BE APPROACHING THE WEST COAST BY THE END OF THE FORECAST WITH STRONGER SHORTWAVE RIDGING AHEAD OF THIS WAVE. THIS IS EVEN A SHIFT FROM THE 12/18Z GFS AND 18Z GEFS SOLUTIONS...ENOUGH SO TO NOT SUPPORT IT MASS-WISE WITHIN THE WPC PREFERENCE WHICH IS NOW NON-GFS AT SLIGHTLY ABOVE AVERAGE CONFIDENCE. PLEASE SEE QPFPFD FOR ADDITIONAL INFORMATION AND SPECIFIC MODEL PREFERENCES FOR QPF. 07Z UPDATE: THE 00Z UKMET TRENDED TO A SLIGHTLY DEEPER WAVE THAN ITS PRIOR RUN WITH AN APPROACHING SURFACE LOW A BIT DEEPER AND FURTHER NORTH IN LINE WITH THE 00Z GFS. THE 00Z GEFS DID SHOW A SURFACE TROF IN THE VICINITY BUT NOT AS DEEP AS EITHER THE GFS/UKMET. LITTLE CHANGE WITH THE CMC/ECMWF LEADS TO A PREFERENCE TO EXCLUDE THE UKMET AS WELL...THOUGH WILL ADD THE GEFS TO PREFERENCE AS A PROXY TO THIS SPREAD/POTENTIAL OF A DEEPER WAVE WITHOUT GOING ALL IN TOWARD THAT SOLUTION. CONFIDENCE IS SLIGHTLY ABOVE AVERAGE. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... GALLINA