434  
FXUS10 KWNH 110447  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1247 AM EDT WED SEP 11 2019  
 
VALID SEP 11/0000 UTC THRU SEP 14/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND, STRONGEST WEIGHTS TO...  
12Z ECMWF ENSEMBLE MEAN, 18Z GEFS MEAN  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
MODELS ARE GENERALLY IN VERY GOOD AGREEMENT WITH THEIR MASS FIELD  
FORECASTS OVER THE NEXT FEW DAYS, WITH LIMITED MODEL SPREAD. THE  
DETERMINISTIC MODELS ARE ALL WELL WITHIN THE ENSEMBLE ENVELOPE.  
THE FLOW PATTERN WILL DEAMPLIFY CONSIDERABLY BY THE END OF THE  
WEEK, WITH A TROUGH LIFTING INTO THE UPPER MIDWEST BY FRIDAY AND  
ZONAL FLOW SETTLING INTO THE NORTHERN TIER OF STATES THEREAFTER.  
 
PERHAPS THE GREATEST MODEL VARIABILITY IS WITH THE PROGRESSION OF  
A TROUGH FROM NEAR THE BAHAMAS WESTWARD INTO THE GULF OF MEXICO.  
MODELS SEEM TO BE FAIRLY SIMILAR IN THEIR DEPICTION OF THE  
AMPLITUDE OF THE WAVE (ALOFT AND AT THE SURFACE), BUT VARY BY AS  
MUCH AS 36-48H AND 700KM IN TIMING. FOR THIS PARTICULAR FEATURE, A  
MEDIAN TIMING CLOSE TO THE ENSEMBLE MEANS (00Z GFS AND 12Z ECMWF  
ARE FAIRLY CLOSE) WAS PREFERRED.  
 
OTHERWISE, A GENERAL MODEL BLEND WITH SOME WEIGHT TOWARD THE  
ENSEMBLE MEANS WAS PREFERRED ACROSS THE REMAINDER OF THE CONUS.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
LAMERS  
 

 
 
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