848  
FXUS10 KWNH 180437  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1136 PM EST SUN NOV 17 2019  
 
VALID NOV 18/0000 UTC THRU NOV 21/1200 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  
LESS WEIGHT ON THE 12Z CMC, 00Z GFS AFTER 20.12Z  
CONFIDENCE: AVERAGE  
 
FOR THE NEXT SEVERAL DAYS, MODELS ARE IN REASONABLY GOOD AGREEMENT  
WITH THE SYNOPTIC PATTERN, AND THE GENERAL PLACEMENT AND MAGNITUDE  
OF QPF. SOME OF THE MORE SUBSTANTIAL SPREAD BY MID-WEEK WILL BE  
RELATED TO TYPICAL TIMING BIAS, AS THE 00Z GFS AND ENSEMBLE  
MEMBERS ARE FASTER WITH PULLING THE CLOSED UPPER LOW OUT OF THE  
SOUTHWEST, WHILE THE 12Z ECMWF AND ENSEMBLE MEMBERS ARE SLOWER.  
GIVEN THE STRENGTH OF THE UPPER LEVEL LOW, AND A RIDGE BUILDING  
OVER THE TOP OF IT IN THE PACIFIC NORTHWEST, THE PREFERENCE IS TO  
LEAN ON THE SLOWER SIDE OF THE MODEL SPREAD, WITH LESS WEIGHT ON  
THE 00Z GFS BY WEDNESDAY.  
 
THERE IS ALSO SOME TIMING SPREAD WITH A SHORTWAVE DIGGING FROM  
CANADA INTO THE GREAT LAKES. IN THIS CASE, THE FASTEST MODEL IS  
THE 12Z CMC, WITH MOST OF THE OTHER DETERMINISTIC MODELS SLOWER  
AND IN BETTER AGREEMENT. THE PREFERENCE IS TO LEAN TOWARD MODEL  
CONSENSUS FOR THIS WAVE, WITH LESS WEIGHT ON THE 12Z CMC BY  
WEDNESDAY AS WELL.  
 
THUS, THE OVERALL MODEL PREFERENCE COULD BE CHARACTERIZED BY A  
GENERAL MODEL BLEND, SHIFTING TOWARD GREATER WEIGHT ON THE 12Z  
ECMWF, 12Z UKMET, AND 00Z NAM BY WEDNESDAY, AND LESS WEIGHT ON THE  
00Z GFS AND 12Z CMC.  
 
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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