Prognostic Meteorological Discussion
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FXUS10 KWNH 261659
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1159 AM EST WED NOV 26 2014

VALID NOV 26/1200 UTC THRU NOV 30/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z NAM/GFS EVALUATION

...LOW PRESSURE OVER THE NORTHERN PLAINS...

THE MODELS CAME INTO GOOD AGREEMENT OVERNIGHT AND THAT AGREEMENT
PERSISTS IN THE 12Z NCEP MODEL RUNS. WITH NO MAJOR CHANGES IN THE
MODELS...SEE NO REASON TO CHANGE THE OVERNIGHT PREFERENCES AT THIS
TIME

...LOW PRESSURE FORMING ALONG THE EAST COAST...

PREFERENCE: HALFWAY BETWEEN THE NAM AND GFS...ESSENTIALLY A MODEL
CONSENSUS
CONFIDENCE: AVERAGE

BOTH THE NAM AND GFS INITIALIZED THE MID LEVEL HEIGHTS ABOUT 25 TO
30 METERS LOWER THAN OBSERVED AT KIAD...WITH 20 METER HEIGHT
DIFFERENCES EXTENDING OVER TO WALLOPS ISLAND AND DOWN TO MOORHEAD
CITY AND BACK TOWARDS JACKSONVILLE.  THERE WERE SIMILAR
DIFFERENCES BETWEEN THE F00 FROM BOTH THE NAM AND GFS OVER BERMUDA
AS WELL.

THE 12Z NCEP GUIDANCE NUDGED WEST FROM THEIR PREVIOUS RUNS...AND
THE HIGHER HEIGHTS OBSERVED TO THE EAST OF THE MID ATLANTIC REGION
SUGGESTS THAT THERE MAY BE ROOM FOR ADDITIONAL WESTWARD PUSH IN
THE MODELS.  STILL...THE AGREEMENT FROM THE 12Z NAM/GFS WAS FAIRLY
GOOD AND DID NOT REPRESENT A MAJOR SHIFT FROM THE PREVIOUS RUNS.
GIVEN LITTLE SHIFT...THE NAM/GFS STILL FIT IN THE PREVIOUS
ENVELOPE OF SOLNS IN ABOUT THE SAME PLACE WHICH LEAVES THE
CANADIAN AS A NORTHERN OUTLIER AND THE OLD ECMWF ON THE WEST SIDE.
 AS MENTIONED IN THE PREVIOUS MODEL DIAGNOSTIC DISCUSSION...THERE
REMAINS ENOUGH SPREAD IN THE MODELS THAT A NAM/GFS COMPROMISE
SHOULD DO WELL AS A MODEL CONSENSUS.

...SHORTWAVE TROUGH INFLUENCING THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES THU/FRI...

PREFERENCE: 26/00Z ECMWF
CONFIDENCE: ABOVE AVERAGE

THE 12Z NAM STILL HAS AN ALLIANCE WITH THE ECMWF AS WELL AS WITH
THE 12Z GFS AND OTHER NON NCEP MODELS AND THE ENSEMBLE MEANS EARLY
ON.  AFTER 12Z FRIDAY...THE GFS BECOMES TOO FAST...LIKE IN
PREVIOUS RUNS...OVER CANADA AND THE NAM TOO PROGRESSIVE WITH THE
SOUTHERN STREAM ENTERING THE WEST COAST.  MEANWHILE...THE 26/00Z
ECMWF LIES NEAR THE MIDDLE OF THE SOLUTION ENVELOPE AND HAS THE
STRONGEST SUPPORT FROM THE ENSEMBLE MEANS.  THEREFORE...RECOMMEND
THE ECMWF REMAINS THE MOST STRONGLY PREFERRED.

...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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