379
FXUS10 KWNH 031838
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
137 PM EST TUE DEC 03 2019
VALID DEC 03/1200 UTC THRU DEC 07/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..OVERALL PATTERN ACROSS THE CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND, LESS WEIGHT ON 12Z GFS BY DAY 3
CONFIDENCE: ABOVE AVERAGE
---18Z UPDATE---
NO CHANGE TO THE PRELIMINARY PREFERENCE AS MODELS REMAIN IN
GENERALLY GOOD AGREEMENT OVERALL.
---PREVIOUS DISCUSSION---
DETERMINISTIC MODELS ARE GENERALLY IN GOOD AGREEMENT WITH THE
SYNOPTIC PATTERN. IN THE 00Z ECMWF ENSEMBLE, THE 500MB SPREAD OVER
THE VAST MAJORITY OF THE CONUS IS BELOW THE PREVIOUS 30-DAY
AVERAGE. THIS SUGGESTS VERY GOOD MODEL SIMILARITY, AND THAT THE
PRIMARY DIFFERENCES OVER THE NEXT FEW DAYS WILL BE WITH MESOSCALE
DETAILS SUCH AS PLACEMENT OF INDIVIDUAL PRECIPITATION BANDS.
THE MOST NOTABLE DIFFERENCES WERE WITH THE 12Z GFS. IT SHOWED A
SHARPER SHORTWAVE TROUGH DIGGING INTO THE SOUTHERN PLAINS ON
THURSDAY, WHICH IS IN CONTRAST TO MOST OTHER MODELS AND THE
EXPECTED DEAMPLIFICATION AS IT PUSHES THROUGH A RIDGE AXIS.
NEVERTHELESS, THIS DOESN'T APPEAR TO HAVE A SIGNIFICANT EFFECT ON
THE QPF. THE GFS IS ALSO SLIGHTLY COLDER WITH LOW-LEVEL
TEMPERATURES IN THE GREAT LAKES. THIS IS IN LINE WITH ITS USUAL
BIAS, BUT THE MAGNITUDE OF THE DIFFERENCE IS SMALL IN THIS CASE.
THEREFORE, SLIGHTLY LESS WEIGHT COULD BE PLACED ON THE GFS BY DAY
3, BUT OVERALL THE PREFERENCE IS FOR A GENERAL MODEL BLEND.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
LAMERS
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