MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1254 AM EDT WED OCT 15 2014 VALID OCT 15/0000 UTC THRU OCT 18/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ============================================== 00Z NAM/GFS EVALUATION AND PRELIM PREFERENCES ============================================== NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT. ============================================== ...BROAD AND DEEP CYCLONE AFFECTING THE EASTERN U.S... PREFERENCE: 00Z GFS CONFIDENCE: AVERAGE THE 18Z GEFS MEAN IS SLOWER THAN THE 12Z EC MEAN WITH WHAT EVOLVES INTO A NEGATIVELY TILTED MID-UPPER LEVEL TROUGH ACROSS THE NORTHEAST BY FRI MORNING. THE 00Z GFS IS CLOSER TO THE EC MEAN...WITH THE 12Z ECMWF FASTER. BOTH THE GFS/ECMWF HOLD GOOD CONTINUITY OVER THEIR PAST 3 12/00Z CYCLES BUT GIVEN THE ENSEMBLE MEANS ARE CLOSE TO OR EVEN A BIT SLOWER THAN THE 00Z GFS...PREFER TO STAY TOWARD THE MIDDLE OF THE LATEST SPREAD...WHICH IS CLOSE TO THE 00Z GFS. REGARDING HURCN GONZALO...THE 00Z GFS IS CLOSER TO THE 03Z NHC TRACK THAN THE SLOWER 00Z NAM AND 12Z ECMWF. THE GFS ADVECTS SOME OF THE MOISTURE CONNECTED TO GONZALO NWD... AHEAD OF A COLD FRONT ASSOCIATED WITH THE UPPER TROUGH...A BIT QUICKER THAN THE SLOWER NAM/ECMWF. WHILE THE 12Z UKMET IS SIMILAR TO THE GFS WITH THE TRACK OF GONZALO...IT IS NOT PREFERRED UPSTREAM WITH THE INTERACTION OF UPPER LEVEL FEATURES INVOF THE GREAT LAKES AND NEW ENGLAND. ...DEEP TROUGH IMPACTING THE NORTHWEST AND EJECTING TO THE NORTHERN PLAINS... PREFERENCE: BLEND OF 12Z ECMWF...12Z CMC CONFIDENCE: AVERAGE WHEN THIS SYSTEM REACHES THE PLAINS AND DEVELOPS A CLOSED 500 MB CONTOUR...CONSECUTIVE UKMET RUNS HAVE BEEN SOUTHERLY OUTLIER WITH THE REMAINING DETERMINISTIC MODEL CONSENSUS WITH BROAD AGREEMENT TO THE NORTH. THE NAM IS IN PRETTY GOOD AGREEMENT UNTIL FRI NIGHT WHEN IT IS A BIT SLOWER WITH THE SHORTWAVE TRACKING THROUGH THE GREAT LAKES WITH THE GFS STILL A BIT FAST WITH THIS FEATURE. THE GFS HAS TRENDED SLOWER THAN ITS PRIOR 12Z RUN HOWEVER...WITH TRENDS AND BETTER ENSEMBLE SUPPORT SUGGESTING A 12Z ECMWF/CMC BLEND TO A BETTER CHOICE FOR THIS REGION FOR FRI/SAT. ...NEXT PACIFIC SYSTEM APPROACHING BY FRIDAY... PREFERENCE: BLEND OF THE OPERATIONAL MODELS CONFIDENCE: AVERAGE THE OPERATIONAL MODELS SHOW GOOD AGREEMENT HERE. ...MID-LEVEL VORTICITY LIKELY REACHING THE BAJA PENINSULA ON FRI... PREFERENCE: BLEND OF THE 00Z NAM...00Z GFS...12Z ECMWF CONFIDENCE: AVERAGE THE NAM/GFS/ECMWF ARE BETTER SUPPORTED BY THE ENSEMBLE MEANS THAN THE FASTER 12Z UKMET AND SLOWER 12Z CMC. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... OTTO