MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 129 AM EDT THU MAY 29 2014 VALID MAY 29/0000 UTC THRU JUN 01/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 00Z NAM/GFS ALONG WITH PRELIMINARY PREFERENCES/FORECAST CONFIDENCE... THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 00Z NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ...QUASI-STATIONARY CLOSED LOW OVER THE LOWER MS VALLEY... PRELIMINARY PREFERENCE: A NON-00Z NAM MODEL COMPROMISE FORECAST CONFIDENCE: AVERAGE A FEATURE WHICH HAS NOT MOVED A WHOLE LOT THE PAST DAY SHOULD REMAIN NEARLY QUASI-STATIONARY ACROSS THE LOWER MS VALLEY BEFORE SLOW RETROGRESSION ON FRIDAY. MOST OF THE UNCERTAINTY LOOMS ENTERING THE EARLY PORTION OF THE WEEKEND WITH HOW THE RESIDUAL CYCLONIC FLOW WILL POSITION ITSELF. THE 00Z NAM IS THE STRONGEST ALOFT AND THE MODEL FURTHEST TO THE SOUTH. ON 01/0000Z...THE 00Z GFS/12Z ECMWF ARE IN LINE WITH THE 18Z GEFS MEAN WHILE THE 12Z CMC/UKMET/ECMWF ENSEMBLE MEAN ARE SLIGHTLY OFF TO THE NORTH CLOSER TO THE RED RIVER. WILL COMFORTABLE REJECTING THE 00Z NAM GIVEN HOW FAR AWAY IT IS FROM THE BETTER CONSENSUS. THE WPC PREFERENCE IS A NON-00Z NAM MODEL COMPROMISE WITH CONFIDENCE REMAINING ONLY AVERAGE GIVEN THE UNCERTAINTY DURING THE WEEKEND. ...DEEP UPPER TROF LIFTING INTO ALBERTA ON THURSDAY... PRELIMINARY PREFERENCE: GENERAL MODEL CONSENSUS FORECAST CONFIDENCE: ABOVE AVERAGE WATER VAPOR IMAGERY SHOWED AN ANOMALOUSLY DEEP UPPER TROF SITUATED ACROSS THE PACIFIC NORTHWEST/UPPER INTERMOUNTAIN WEST. DOWNSTREAM HEIGHT RISES WILL FORCE THE SYSTEM UP INTO ALBERTA/SASKATCHEWAN WITH BROAD SOUTHWESTERLY FLOW REMAINING IN THE WAKE. THE MODELS ARE GENERALLY IN AGREEMENT SO A CONSENSUS SOLUTION WILL BE RECOMMENDED. ...SHORTWAVE ENERGY SLIDING FROM NORTHERN CA INTO THE CENTRAL GREAT BASIN FRIDAY THRU SUNDAY... PRELIMINARY PREFERENCE: BLEND OF THE 00Z GFS WITH THE 12Z ECMWF/ECMWF ENSEMBLE MEAN FORECAST CONFIDENCE: BELOW AVERAGE AS THE LEAD SYSTEM LIFTS UP INTO SASKATCHEWAN...ANOTHER SYSTEM IS FORECAST TO SLIDE SOUTHWARD ALONG THE WEST BEFORE TURNING EASTWARD OVER NORTHERN CA. BY FRIDAY MORNING...THE 12Z UKMET IS EAST OF THE GLOBAL ENSEMBLE MEANS WHICH IS ALSO SOMEWHAT ACCOMPANIED BY THE 12Z CMC. ADDITIONAL REPLENISHMENT OF THIS FEATURE IS ANTICIPATED AS A CLOSED LOW FILLS IN FROM THE NORTH ON FRIDAY. THE 576-DM SPAGHETTI PLOTS DEPICT QUITE A BIT OF SPREAD...EVEN MORE SO THAN 36 HOURS AGO. MUCH OF IT HAS TO DO WITH HOW QUICKLY THE SYSTEM EJECTS EASTWARD. THE 12Z GEFS MEMBERS ARE A BIT MORE AMPLIFIED AND TOWARD THE WEST WHILE THE 12Z ECMWF ENSEMBLE MEMBERS ARE FLATTER/MORE PROGRESSIVE. INTERESTINGLY THE 00Z GFS LOOKS MORE LIKE THE 12Z ECMWF/ECMWF ENSEMBLE MEAN COMBINATION. FOR NOW WILL FAVOR A COMBINATION OF THE 00Z GFS WITH THE 12Z ECMWF/ECMWF ENSEMBLE MEAN PENDING FUTURE GUIDANCE. ...NORTHERN STREAM SYSTEM TRACKING THROUGH THE NORTHEASTERN U.S. ON FRIDAY... PRELIMINARY PREFERENCE: BLEND OF THE 00Z GFS WITH THE 12Z ECMWF/CMC FORECAST CONFIDENCE: AVERAGE AN ACTIVE NORTHERN STREAM OF THE JET WILL ALLOW AN UPPER TROF TO DIVE SOUTHEASTWARD FROM ONTARIO/QUEBEC DOWN ACROSS NEW ENGLAND AND EVENTUALLY INTO THE WESTERN ATLANTIC. AT THIS POINT IN TIME...THE 00Z NAM APPEARS TO THE MOST AGGRESSIVE IN TERMS OF SPEED AND ALSO DEPICTS A SURFACE LOW OFF TO THE WEST OF THE BETTER MODEL CLUSTERING. A BLEND OF THE 00Z GFS AND 12Z ECMWF/CMC APPEAR TO THE MOST MIDDLE GROUND SOLUTIONS AND ALSO AGREE MORE WITH THE ENSEMBLE MEANS. ...BATCH OF ENERGY LIFTING FROM THE SOUTHERN ROCKIES UP INTO THE NORTHERN PLAINS... PRELIMINARY PREFERENCE: A NON-00Z NAM MODEL COMPROMISE FORECAST CONFIDENCE: AVERAGE A BROAD PLUME OF ENERGY LIFTING FROM NORTHERN MEXICO UP THROUGH THE SOUTHERN ROCKIES IS WELL AGREED UPON IN THE MODELS. ONE MAJOR DIFFERENCE IS THE 00Z NAM IS EAST OF A MAJORITY OF THE GUIDANCE WITH WHERE THE BATCH OF ENERGY LIFTS NORTHWARD ALONG AND EAST OF THE ROCKIES. WILL FAVOR A NON-00Z NAM MODEL COMPROMISE TO ACCOUNT FOR THIS. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RUBIN-OSTER