MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 148 PM EST WED FEB 26 2014 VALID FEB 26/1200 UTC THRU MAR 02/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 12Z CMC/UKMET/ECMWF ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ...INITIAL CLIPPER SYSTEM LIFTING INTO COASTAL NEW ENGLAND BY WEDNESDAY AFTERNOON... ...PAIR OF SURFACE LOWS TRACKING ALONG THE WESTERN ATLANTIC... FINAL PREFERENCE: GENERAL MODEL CONSENSUS FORECAST CONFIDENCE: ABOVE AVERAGE THE LEAD SYSTEM WITHIN THE BROAD CYCLONIC FLOW ACROSS THE NORTHEASTERN PORTION OF NORTH AMERICA WILL QUICKLY LIFT FROM THE MID-ATLANTIC UP INTO COASTAL NEW ENGLAND EARLY THIS AFTERNOON. MODELS ARE IN SUFFICIENT AGREEMENT ALOFT DURING THE NEXT 6 TO 12 HOURS AS THE TROF LIFTS UP INTO NOVA SCOTIA BY THIS EVENING. AT THE SURFACE...THERE IS SLIGHT DISAGREEMENT WITH THE PLACEMENT OF THE PAIR OF WAVES ALONG THE FRONT BUT THEY ARE RESTRICTED TO THE OFFSHORE WATERS OF THE ATLANTIC. THUS WILL RECOMMEND A GENERAL MODEL CONSENSUS. ...SECONDARY UPPER TROF SWINGING THROUGH THE GREAT LAKES AND INTO NEW ENGLAND THROUGH 28/0000Z... ...SURFACE LOW FILLING WHILE TRAVERSING THE GREAT LAKES... FINAL PREFERENCE: BLEND OF THE 12Z GFS/CMC WITH THE 12Z GEFS/09Z SREF MEANS FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE WITH THE LEAD ENERGY LIFTING TOWARD FAR EASTERN CANADA...ANOTHER AXIS OF HEIGHT FALLS WILL RACE FROM THE UPPER MIDWEST/GREAT LAKES TOWARD NEW ENGLAND THROUGH THURSDAY EVENING. DIFFERENCES ARE FAIRLY MINIMAL EARLY ON BUT EVENTUALLY GROW IN TIME WITH THE SURFACE EVOLUTION BECOMING MORE COMPLEX. MODELS ADVERTISE A MYRIAD OF SURFACE LOWS CROSSING FAR EASTERN QUEBEC ALONG WITH COASTAL NEW ENGLAND. THE 12Z GFS/CMC ARE MORE IN AGREEMENT WITH THE 12Z GEFS/09Z SREF MEANS WHILE AS EXPECTED THE 12Z ECMWF/00Z ECMWF ENSEMBLE MEAN FOLLOW ONE ANOTHER MORE READILY. MEANWHILE THE 12Z/00Z UKMET DIFFERS FROM EITHER SOLUTION BEING MORE OFF TO THE EAST. AS THERE HAVE NOT BEEN SIGNIFICANT CHANGES SEEN WITH THE ARRIVAL OF THE 12Z GUIDANCE...WILL MAINTAIN THE PREFERENCE FROM EARLIER. ...ADDITIONAL SHORTWAVE ENERGY NEARING THE MN/ND BORDER BY LATE SATURDAY... ...UPPER LOW SPLITTING OFF AND RETROGRADING BACK TOWARD BRITISH COLUMBIA/ALBERTA... FINAL PREFERENCE: BLEND OF THE 12Z ECMWF WITH THE 12Z GEFS/00Z ECMWF ENSEMBLE MEANS FORECAST CONFIDENCE: BELOW AVERAGE THE EVOLUTION OF THE SYSTEM ACROSS CANADA WILL BE QUITE COMPLEX AS THE EXPANSIVE CLOSED LOW CONTINUES ITS DOMINANCE OVER NORTHEASTERN NORTH AMERICA. AS THIS SYSTEM GENERALLY REMAINS IN PLACE...ANOTHER BATCH OF ENERGY WILL PEEL OFF TOWARD THE WEST SETTLING OVER WESTERN CANADA BY 02/0000Z. RELATIVE TO THE ENSEMBLE MEANS...THE 12Z CMC/UKMET ARE FURTHER TO THE EAST WITH THE WESTERN CANADIAN TROF WHICH DOES NOT ADVERTISE THE SYSTEM CLOSING OFF AS DEPICTED IN THE REMAINING GUIDANCE. WILL FAVOR THE CLOSED OFF SOLUTION PER ENSEMBLE MEANS WITH THE 12Z ECMWF BEING CLOSEST TO THE IDEAS DEPICTED BY THE MEANS. WILL CONTINUE TO RECOMMEND A COMBINATION OF THE 12Z ECMWF WITH THE 00Z ECMWF ENSEMBLE MEAN...BUT WILL ADD THE 12Z GEFS MEAN TO THE MIX AS IT AGREES WITH THIS OTHER GUIDANCE. ...STRONG PACIFIC SYSTEM REACHING NORTHERN CA BY 27/0600Z... ...SHEARING ENERGY RACING ACROSS THE OZARKS AND INTO THE LOWER MID-ATLANTIC... FINAL PREFERENCE: THROUGH 27/1200Z: GENERAL MODEL CONSENSUS...BEYOND: BLEND OF THE 12Z ECMWF WITH THE 12Z GEFS/00Z ECMWF ENSEMBLE MEANS FORECAST CONFIDENCE: INITIALLY ABOVE AVERAGE...THEN BECOMING AVERAGE THE FIRST IN A PAIR OF SYSTEMS AFFECTING CA WILL REACH NORTHERN CA BY WEDNESDAY NIGHT. AS THE UPPER LOW BEGINS TO SHEAR ACROSS THE SIERRA NEVADA RANGE...THE 12Z NAM/09Z SREF MEAN BECOME A BIT SLOWER ADVANCING THE MID-LEVEL HEIGHT FALLS FURTHER INLAND. THE 12Z GFS EVENTUALLY JOINS THE SLOWER NAM/SREF MEAN SOLUTION WHILE THE 12Z CMC/UKMET ARE ON THE SLIGHTLY FASTER SIDE. SITTING SOMEWHERE IN THE MIDDLE ARE THE 12Z ECMWF/00Z ECMWF ENSEMBLE MEAN. THESE MODEL DIFFERENCES CONTINUE WHILE THE SYSTEM SHEARS A BIT ACROSS THE OZARKS/TN VALLEY. FEEL SAFER STAYING CLOSER TO THE CENTER OF THE SPREAD WHICH FAVORS THE 12Z ECMWF ALONG WITH THE 12Z GEFS/00Z ECMWF ENSEMBLE MEANS. HOWEVER...FOR THE FIRST DAY OF THE PERIOD...A GENERAL MODEL CONSENSUS WILL BE FINE GIVEN THE MINIMAL SPREAD. ...ANOMALOUS CLOSED LOW APPROACHING CA BY EARLY FRIDAY... ...WELL-DEVELOPED SURFACE CYCLONE WEAKENING IN TIME... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF WITH THE 00Z ECMWF ENSEMBLE MEAN FORECAST CONFIDENCE: AVERAGE A POWERFUL SUB 528-DM CLOSED LOW WILL BEGIN TO MOVE EAST OF 130W LONGITUDE BY EARLY FRIDAY AS IT SLOWLY WORKS ITS WAY TOWARD CA BY THE END OF THE WORK WEEK. THE 12Z GEFS MEAN IS ONE OF THE QUICKER SOLUTIONS IN CARRYING THIS PACIFIC ENERGY TOWARD THE CA COAST WITH OTHER ENSEMBLE MEANS SUPPORTING SOMETHING A BIT FURTHER WEST. THE LATEST 12Z GFS HAS TRENDED AWAY FROM THAT FASTER SOLUTION OF THE 12Z/06Z GEFS MEAN AND LEANED MORE CLOSELY TO THE 12Z ECMWF/00Z ECMWF ENSEMBLE MEAN. THIS IDEA APPEARS FAIRLY STABLE AND REMAINS CENTERED IN THE MIDDLE OF THE GUIDANCE WITH THE 12Z NAM BEING ON THE FAR WESTERN SIDE WHILE THE 00Z CMC BECOMES MORE PROGRESSIVE. THE PREFERENCE WILL BE A BLEND OF THE 12Z GFS/ECMWF WITH THE 00Z ECMWF ENSEMBLE MEAN. www.wpc.ncep.noaa.gov/html/model2.shtml... RUBIN-OSTER