Prognostic Meteorological Discussion
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000 FXUS10 KWNH 221653 PMDHMD MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1253 PM EDT TUE JUL 22 2014 VALID JUL 22/1200 UTC THRU JUL 26/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 12Z NAM/GFS EVALUATION...INCLUDING PRELIMINARY PREFERENCES MID LEVEL LOW SLOWLY RETROGRADING OVER THE GULF COAST STATES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z GFS / 00Z ECMWF BLEND CONFIDENCE: ABOVE AVERAGE THE MODELS AGREE ON WEAKENING THIS FEATURE ALONG WITH INCREASING SHEARING AS THE LOW SLOWLY RETROGRADES WWD ALONG THE GULF COAST. THE 00Z UKMET/CMC APPEAR TOO WEAK WITH THE 500 MB LOW COMPARED TO THIS MORNINGS 12Z RAOB DATA. IT IS ALSO THE UKMET/CMC THAT ARE WEAKEST WITH THIS LOW AS IT TRACKS WWD INTO SOUTH TEXAS. ON THE OTHER SIDE...THE 12Z NAM WHILE INITIALIZED WELL...IS THE SLOWEST OF THE DETERMINISTIC MODEL SUITE. THE 12Z GFS AND 00Z ECMWF SHOW GOOD CONTINUITY WITH THEIR PREVIOUS 12/00Z RUNS AND ARE PREFERRED DUE TO THEIR PLACEMENT IN THE MIDDLE OF THE DETERMINISTIC/ENSEMBLE SPREAD. CLOSED LOW PASSTING THROUGH THE NORTHWEST WED/THU SURFACE LOW PRESSURE DEVELOPING IN THE LEE OF THE NORTHERN ROCKIES ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 12Z NAM / 00Z ECMWF BLEND CONFIDENCE: AVERAGE THE 12Z GFS IS SOUTH AND THE 00Z UKMET IS NORTH OF THE REMAINING DETERMINISTIC/ENSEMBLE CONSENSUS REGARDING THE CLOSED LOW AS IT MOVES THROUGH ALBERTA INTO SASKATCHEWAN. THESE DIFFERENCES BEGIN TO APPEAR AROUND 12Z/24 AND GROW WTIH TIME. THE NAM/ECMWF SHOW THE BEST AGREEMENT TO THE ENSEMBLE MEANS AND LIE IN THE MIDDLE OF THE MODEL SPREAD REGARDING THE 500 MB LOW CENTER AND THE CORRESPONDING SURFACE LOW TRACKING ACROSS THE CNTRL/NRN PLAINS. BROADER UPPER LEVEL TROUGH CROSSING THE GREAT LAKES AND INTO THE NORTHEAST BY FRI MORNING COLD FRONT CROSSING THE OHIO VALLEY AND MID-ATLANTIC REGION ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: GENERAL MODEL COMPROMISE CONFIDENCE: ABOVE AVERAGE ALL THE MODELS SHOW GOOD AGREEMENT HERE SO WILL PREFER A GENERAL MODEL COMPROMISE TO IRON OUT SMALLER SCALE DIFFERENCES. ...MODEL TREND GRAPHICS AT www.wpc.ncep.noaa.gov/html/model2.shtml... ...500 MB FORECASTS AT www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... OTTO $$

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