Prognostic Meteorological Discussion
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000 FXUS10 KWNH 220700 PMDHMD MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 259 AM EDT MON SEP 22 2014 VALID SEP 22/0000 UTC THRU SEP 25/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ============================================== 00Z MODEL EVALUATION AND PREFERENCES ============================================== NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT. ============================================== ...EASTERN U.S INTO TUESDAY... PREFERENCE: ANY OF THE OPERATIONAL MODELS CONFIDENCE: ABOVE AVERAGE A WELL DEFINED CYCLONE WILL PUSH EAST FROM NEW ENGLAND...ABSORBING A COASTAL LOW LIFTING UP FROM THE CAROLINAS. MODEL SPREAD IS MINIMAL. THE ECMWF IMPROVED UPON ITS SURFACE SOLUTION WITH RESPECT TO THE COASTAL LOW. ...EASTERN U.S LATE TUE THRU WED INTO EARLY THU... PREFERENCE: 12Z ECMWF ENSEMBLE MEAN...WITH GROWING SUPPORT CONFIDENCE: AVERAGE WHILE THE 00Z MODELS DISPLAYED SOME DIFFERENCES BY LATE TUESDAY...THE SPREAD GETS LARGER THROUGHOUT THE REMAINDER OF DAY 2 INTO DAY 3. EARLIER RECOMMENDATION FOR USING THE ECMWF ENSEMBLE MEAN STILL LOOKS GOOD CONSIDERING ITS CONSISTENCY. THE GEFS SUPPORT OF THE 21/12Z OR 22/00Z GFS WAS NOT AS GOOD...ESPECIALLY ON DAY 3. SO WILL CONTINUE TO RECOMMEND THIS IDEA. THE HEIGHTS AND POSITION OF THE TROF AND EMBEDDED FEATURES FROM THE 22/00Z RUN OF THE ECMWF LOOKED TOO DEEP BY THE END OF DAY 3 TO PROVE USEFUL. THINK THE OLD ECENS MEAN AND THE PREVIOUS RUN OF THE ECMWF WOULD BE A BETTER BET. ...SHEAR AXIS TRAPPED IN THE UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS... PREFERENCE: BLEND OF THE OPERATIONAL MODELS CONFIDENCE: AVERAGE THE 00Z MODELS STILL STRUGGLE TO MAINTAIN DEFINITION WITH A 850 TO 700 MB SHEAR AXIS TRAPPED BENEATH AN UPPER LEVEL RIDGE. THE MODEL SOLUTIONS ARE SIMILAR BUT CONFIDENCE REGARDING DETAILS OF CONVECTION IN A QUASI TROPICAL AIRMASS DECREASES WITH TIME OWING TO CONTINUED SMALL SCALE FEEDBACK BEING OBSERVED AND NOT OFTEN APPEARING IN THE MODELS. ...SYSTEM TRACKING FROM THE GREAT BASIN INTO THE PLAINS... PREFERENCE: BLEND OF 00Z GFS/ECMWF/UKMET CONFIDENCE: AVERAGE THERE HAS BEEN A TREND FOR THE MODELS TO SLOW THIS SYSTEM AND DEPICT A SOMEWHAT MORE PRONOUNCED CIRCULATION BY THE TIME IT PULLS INTO THE CENTRAL PLAINS...ALTHOUGH THE GFS AND ECMWF BEGAN TO TAKE INDIVIDUAL SHORTWAVES EASTWARD MORE QUICKLY. BLENDING THE 00Z GFS/UKMET/ECMWF SHOULD KEEP THE ESSENCE OF THE LARGE SCALE FEATURE WHILE MITIGATING SOME OF THE PROBLEMS WITH THE MINOR SHORTWAVES. ...DEEP TROUGH WITH INCREASING IMPACT TO THE PACIFIC NORTHWEST... PREFERENCE: BLEND OF THE 00Z OPERATIONAL MODELS CONFIDENCE: ABOVE AVERAGE THIS TROUGH WILL BEING TO PRODUCE MORE MEANINGFUL IMPACTS AND WIDESPREAD RAIN BY WEDNESDAY. MODEL SPREAD IS MINIMAL. ...MODEL TREND GRAPHICS AT www.wpc.ncep.noaa.gov/html/model2.shtml... ...500 MB FORECASTS AT www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN $$

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