Prognostic Meteorological Discussion
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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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