MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1139 PM EST FRI JAN 10 2014 VALID JAN 11/0000 UTC THRU JAN 14/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NAM/GFS EVALUATION NO SIGNIFICANT INITIALIZATION ERRORS APPEAR TO BE IMPACTING THE SHORT RANGE FORECAST. ...PROGRESSIVE UPPER TROUGH GOING NEG-TILT ALONG THE EAST COAST BY SUN... PREFERENCE: NON NAM MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE THE LATEST MODELS CONTINUE TO ADVERTISE AN UPPER TROUGH WHICH ADVANCES QUICKLY FROM THE GREAT LAKES/OH VALLEY EARLY THIS EVENING AND REACHES THE EASTERN U.S. SATURDAY AND SUNDAY...EVENTUALLY GOING NEGATIVE TILT AS THE SYSTEM IS ABOUT TO MOVE OUT TO SEA. THE GFS HAD BETTER CONTINUITY WITH THIS SYSTEM WHILE THE NAM REALLY SLOWS DOWN THE EASTWARD PROGRESSION. SINCE THE GFS STILL HAS SUPPORT FROM THE DAYTIME MODEL RUNS FROM NON NCEP CENTERS AND FROM THE ENSEMBLES...WILL NOT PUT A LOT OF WEIGHT ON THE NAM IDEA AT THIS POINT. ...INTENSE UPPER TROUGH/CLOSED LOW RAPIDLY CROSSING THE NORTHWEST LATER TONIGHT AND SAT... ...ENERGY ADVANCING DOWNSTREAM ACROSS SOUTHERN CANADA AND THE CENTRAL U.S. THROUGH SUN... PREFERENCE: 12Z GFS CONFIDENCE: AVERAGE THE LATEST WV/IR SAT IMAGERY CONTINUES TO SHOW VORT ENERGY AMPLIFYING RATHER SHARPLY ATTM SOUTH OF THE ALEUTIANS. THE MODELS SHOW THIS ENERGY SHOULD CONTINUE TO AMPLIFY OVERNIGHT WHICH DRIVES INTENSE SFC LOW PRESSURE AND BROAD AND VERY STRONG WIND FIELD INTO THE NORTHWEST AND SOUTHERN BRITISH COLUMBIA LATER TONIGHT. ON SAT...RATHER STRONG LOW PRESSURE WILL REDEVELOP IN THE LEE OF THE CANADIAN ROCKIES AND CROSS SOUTHERN CANADA THROUGH SUN. A TRAILING PACIFIC FRONT WILL ADVANCE EAST OUT OF THE WESTERN U.S. AND THROUGH THE PLAINS FOR SUN. ON MON...LOW PRESSURE WILL MOVE INTO SERN CANADA...WITH THE TRAILING FRONT ENTERING THE EASTERN U.S. THE NAM WAS SLOWER THAN ITS PREVIOUS RUN AND HAD MINIMAL SUPPORT FROM THE 21Z SREF WHILE THE GFS WAS IN BETTER AGREEMENT WITH ITS PREVIOUS RUN AND HAD ENSEMBLE SUPPORT. THE 00Z RUNS OF THE NAM AND THE GFS STILL DID LITTLE IN THE WAY OF STREAM SEPARATION OVER THE LOWER MS VALLEY ON MONDAY. GIVEN THE RUN TO RUN CONTINUITY...THE 00Z GFS APPEARS TO BE A REASONABLE SOLN ATTM. ...WARM FRONT ARRIVING ACROSS THE PACIFIC NORTHWEST BY LATE SUN... ...LOW PRESSURE/FRONT OVER THE NORTHERN PLAINS/SOUTHERN CANADA MON... PREFERENCE: GENERAL MODEL COMPROMISE...11/12Z GEFS OVER THE NORTHWEST CONFIDENCE: ABOVE AVERAGE OVER THE NORTHWEST...TRANSITIONING TO BELOW AVERAGE OVER THE PLAINS IN THE WAKE OF THE POWERFUL TROUGH/SFC LOW IMPACTING THE NORTHWEST ON SAT...A WARM FRONT IS SUGGESTED BY THE MODELS TO ARRIVE ACROSS THE PACIFIC NORTHWEST ON SUN. VERY FAST ZONAL UPSTREAM FLOW ACROSS THE CENTRAL/EASTERN PACIFIC OCEAN WILL FAVOR THIS FRONT ARRIVING QUICKLY...AND ALL OF THE LATEST MODELS AGREE AND CLUSTER WELL ON THIS SCENARIO. A GENERAL MODEL COMPROMISE WILL BE FAVORED AS THIS NEXT FRONT ARRIVES SUN. ON MON...SHORTWAVE ENERGY ASSOCD WITH THE WARM FRONT ARRIVAL WILL ADVANCE OUT INTO THE PLAINS AND SOUTHERN CANADA. THE 00Z NAM WAS LESS PROGRESSIVE THAN IT WAS EARLIER WHILE THE 12Z GFS WAS ONLY A TAD SLOWER AND REMAINED ON THE WEAKER SIDE OF SOLNS. THE 11/12Z UKMET AND 12Z GEM GLOBAL ALL SHOW MORE SIGNIFICANT LOWERING OF SFC PRESSURES AND A WELL-DEFINED LOW CENTER DEVELOPING AND OVER SOUTHWEST CANADA AND TWD THE U.S./CANADIAN BORDER. THE 11/12Z ECMWF WAS WEAKER AT LEAST THROUGH THIS TIME FRAME. WITH LIMITED CONFIDENCE...WILL FAVOR THE 12Z GEFS MEAN ATTM WITH THIS LOW PRESSURE DEVELOPMENT AND ASSOCD FRONT. ...MODEL TREND GRAPHICS AT www.wpc.ncep.noaa.gov/html/model2.shtml... BANN