880  
FXUS10 KWNH 041832  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
231 PM EDT SUN AUG 04 2019  
 
VALID AUG 04/1200 UTC THRU AUG 08/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 12Z GFS, 12Z CMC AND 12Z ECMWF  
CONFIDENCE: ABOVE AVERAGE  
 
THE SYNOPTIC PATTERN CONTINUES TO LOOK RELATIVELY CONSISTENT, WITH  
A PERSISTENT RIDGE IN THE WESTERN U.S. AND A TROUGH OVER THE EAST  
THAT GETS REINFORCED BY SOME DIGGING SHORTWAVES EMBEDDED WITHIN  
DEEPER LAYER NORTHWEST FLOW ALOFT. DETERMINISTIC MODELS ARE IN  
FAIRLY GOOD AGREEMENT, AND ECMWF ENSEMBLE SPREAD IS BELOW THE  
PREVIOUS 30-DAY AVERAGE IN MANY AREAS -- INDICATING GENERALLY  
BETTER THAN AVERAGE MODEL SIMILARITY FOR MID-SUMMER.  
 
A BLEND OF THE 12Z GFS, 12Z CMC, AND 12Z ECMWF IS THE PREFERENCE  
AT THIS TIME ACROSS THE CONUS. DIFFERENCES AMONG THESE MODELS ARE  
MODEST AND THEY TEND TO HAVE GOOD ENSEMBLE SUPPORT. A BLEND OF  
THESE SHOULD ALSO RESOLVE ANY SMALLER SCALE DETAIL DIFFERENCES  
RELATING TO CONVECTIVE PROCESSES AND SMALLER SCALE VORT-MAXIMA.  
 
THE 12Z NAM AND 12Z UKMET REMAIN A BIT OUTSIDE THE ENVELOPE OF  
NAEFS AND ECMWF ENSEMBLE HEIGHT SPREAD IN SOME AREAS, MOSTLY  
SURROUNDING THE TROUGH IN THE EAST ON TUESDAY AND WEDNESDAY. THE  
UKMET ONCE AGAIN SHOWS A STRONGER RIDGE OVER THE SOUTHWEST THAN  
ANY OTHER DETERMINISTIC MODEL, AND A LESS AMPLIFIED TROUGH IN THE  
EAST, WITH MINIMAL ENSEMBLE SUPPORT. MEANWHILE, THE NAM SHOWS A  
STRONGER SHORTWAVE DIGGING ACROSS PORTIONS OF THE UPPER MIDWEST,  
GREAT LAKES AND OH VALLEY TUESDAY INTO WEDNESDAY. GIVEN A LACK OF  
ENSEMBLE SUPPORT, THESE MODELS ARE NOT INCLUDED IN THE PREFERENCE  
AT THIS TIME.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON/LAMERS  
 

 
 
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