FXUS10 KWNH 070506 PMDHMD MODEL DIAGNOSTIC DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 105 AM EDT SUN SEP 07 2008 VALID SEP 07/0000 UTC THRU SEP 10/1200 UTC MODEL INITIALIZATION... ...SEE NOUS42 KWNO ADMNFD FOR STATUS OF UPPER AIR INGEST... HANNA... THE NAM WAS 20-35 METERS TOO LOW WITH THE 500 HPA HEIGHTS ASSOCIATED WITH HANNA...WHILE THE GFS ERRORS RANGED FROM 10-25 METERS. THIS COULD MEAN ITS FORECAST SOLUTION ALOFT IS TOO DEEP. AT THE SURFACE...THE NAM PRESSURE PATTERN IS SLIGHTLY WEAK OUTSIDE ITS CORE...ON AVERAGE BY 2 HPA...WHILE THE GFS ERRORS ARE CLOSER TO 4 HPA. WITHIN THE CORE...THE ERROR INCREASES UP TO 6-7 HPA WITHIN THE NAM AND GFS INITIALIZATIONS. MODEL TRENDS... STRONG SHORTWAVE DROPPING THROUGH WESTERN CANADA TUESDAY... THE NAM HAS TRENDED SLIGHTLY DEEPER WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS. THE ECMWF IS IN THE MIDDLE OF ITS PAST COUPLE DAYS OF RUNS WITH THIS SYSTEMS POSITION AND DEPTH. THE GFS HAS TRENDED STRONGER/MORE SOUTHWEST WITH THIS ENERGY LATE IN THE PERIOD OVER ITS PAST DAY OF RUNS. SHORTWAVE MOVING THROUGH THE GREAT LAKES EARLY TUESDAY... THE NAM/GFS HAVE WAVERED WITH THIS SYSTEMS DEPTH OVER ITS PAST DAY OF RUNS...AS THEIR 06/00Z RUNS WERE SLIGHTLY WEAKER...AND THEIR 12Z RUNS WERE A BIT STRONGER/SLOWER. THE ECMWF HAS TRENDED SLIGHTLY STRONGER/SLOWER WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS. SHORTWAVE MOVING THROUGH NEW ENGLAND SUNDAY NIGHT... THE NAM/GFS HAVE TRENDED STRONGER WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS. THE ECMWF HAS TRENDED STRONGER WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS. HANNA... THE NAM HAS TRENDED FASTER WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS...WHICH IS DRIVEN BY ITS PROPER LOCATION WITHIN ITS INITIALIZATION. THE ECMWF HAS TRENDED SLIGHTLY QUICKER WITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS FOR THE SAME REASON. THE GFS HAS MAINTAINED EXCELLENT CONTINUITY WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS. IKE... THE NAM HAS TRENDED FASTER WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS...WHICH IS DRIVER BY ITS PROPER LOCATION WITHIN ITS INITIALIZATION. THE ECMWF HAS WAVERED A BIT ON ITS TRACK WITH THIS SYSTEM...WITH THE MOST RECENT RUN AND 05/00Z RUN THE FARTHEST NORTHEAST SOLUTIONS. THE GFS HAS MAINTAINED VERY GOOD CONTINUITY WITH THIS SYSTEM OVER ITS PAST DAY OF RUNS POSITIONWISE...WHILE DEPTHWISE IT FINALLY APPEARS TO REALIZE THE SYSTEM IS A TROPICAL CYCLONE AND NOT A SHALLOW LOW. ...MODEL TREND GRAPHICS AT WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... MODEL DIFFERENCES AND PREFERENCES... STRONG SHORTWAVE DROPPING THROUGH WESTERN CANADA TUESDAY... THE GFS IS THE MOST SOUTHWEST OF THE GUIDANCE WITH THIS SYSTEM AS IT MOVES NEAR THE PACIFIC NORTHWEST WEDNESDAY MORNING...AND HAS ALSO MAINTAINED THE WORST CONTINUITY. THE REMAINDER OF THE GUIDANCE IS IN GENERAL AGREEMENT...THOUGH THE NAM IS THE STRONGEST PIECE OF GUIDANCE AMONGST THE CONSENSUS. SINCE THIS SYSTEM LIES ON THE SOUTHWEST SIDE OF THE POLAR VORTEX...A MORE NORTHEAST SOLUTION SIMILAR TO THE ECMWF-LED CONSENSUS IS IDEAL...AND WILL BE PREFERRED. SHORTWAVE MOVING THROUGH THE GREAT LAKES EARLY TUESDAY... THE GFS IS THE STRONGEST PIECE OF GUIDANCE WITH THIS SYSTEM AS IT ROUNDS THE BASE OF THE POLAR VORTEX IN NUNAVUT. MODEL TRENDS ARE IRREGULARLY STRONGER AMONGST THE GFS/NAM RUNS OF THE PAST DAY...BUT EVEN THE ECMWF TRENDS SUPPORT A SLIGHTLY STRONGER SOLUTION. WILL SUPPORT AN ECMWF/GFS COMPROMISE HERE PER THE TRENDS...SIMILAR TO THE CANADIAN SOLUTION...WITH THIS FEATURE. SHORTWAVE MOVING THROUGH NEW ENGLAND SUNDAY NIGHT... THE GFS/CANADIAN SOLUTIONS ARE SLIGHTLY STRONGER THAN THE REMAINDER OF THE GUIDANCE WITH THIS SHORTWAVE. THE TRENDS SUPPORT A STRONGER SOLUTION. PER THE MODEL TRENDS...WILL SUPPORT A STRONGER SOLUTION SIMILAR TO AN ECMWF/GFS COMPROMISE WITH THIS SYSTEM. HANNA... THE MODELS ARE IN EXCELLENT AGREEMENT WITH THIS SYSTEM...THOUGH THEY ALL SLIGHTLY OUTPACE THE OFFICIAL NHC TRACK. SEE THE LATEST ADVISORIES/DISCUSSIONS ON THIS SYSTEM...WHICH IS BECOMING AN EXTRATROPICAL CYCLONE. IKE... THE NAM IS THE MOST NORTHERLY SOLUTION WITH THIS INTENSE HURRICANE...WHILE THE UKMET AND 18Z NCEP ENSEMBLE MEAN ARE THE MOST SOUTHERLY. ALTHOUGH THE ENSEMBLE SPREAD AMONGST THE GEFS/ECMWF/CANADIAN MEMBERS IS NARROWING...ALL OF THESE SOLUTIONS ARE ON THE SLOW/EAST SIDE OF THE ENSEMBLE SPREAD...AND THE TREND AMONGST THE ENSEMBLE MEMBERS IS QUICKER OVER THEIR PAST COUPLE DAYS OF RUNS. THE GFS HAS SHOWN THE BEST CONTINUITY WITH IKE SINCE YESTERDAY. SEE THE LATEST ADVISORIES/DISCUSSIONS FROM NHC CONCERNING THIS SYSTEM. ...500 MB FORECASTS AT WWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... ROTH $$