085  
FXUS10 KWNH 071951  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
351 PM EDT WED AUG 07 2019  
 
VALID AUG 07/1200 UTC THRU AUG 11/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS  
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: AVERAGE  
 
MODEL MASS FIELDS ARE IN VERY GOOD AGREEMENT INTO FRIDAY NIGHT,  
WITH THE MAIN ISSUE BEING QPF PLACEMENT AND MAGNITUDE ALONG A LOW  
MOVING COLD FRONT OVER THE SOUTH-CENTRAL CONUS ON FRIDAY AND AHEAD  
OF ANOTHER COLD FRONT OVER THE NORTHERN PLAINS ON SATURDAY. A  
BROAD-BASED MODEL BLEND IS PREFERRED FOR MASS FIELDS WITH HIGHER  
RESOLUTION FOR QPF GIVEN THEIR ABILITY TO PLACE CONVECTIVE PRECIP  
FARTHER TOWARD INSTABILITY POOLS.  
 
A COLD FRONT STALLS OVER THE SOUTH-CENTRAL CONUS LATE FRIDAY WITH  
ASSOCIATED PRECIP FOR DAY 2 VARIED IN PLACEMENT AND MAGNITUDE  
ALONG THIS FRONT. THE 12Z NAM NEST IS THE FARTHEST SOUTH WITH THIS  
PRECIP WHICH IS FARTHER INTO THE INSTABILITY POOL WHICH IS TYPICAL  
OF CONVECTIVE ALLOWING MODELS VS GLOBAL DETERMINISTIC.  
 
DIFFERENCES IN THE SYNOPTIC SCALE BEGIN TO EMERGE FRIDAY NIGHT  
WITH THE PROGRESSION OF A TROUGH INTO THE WEST COAST. THE 12Z GFS  
IS THE MOST PROGRESSIVE INLAND WHICH WOULD CREATE DIFFERENCES IN  
SHORTWAVE TROUGH PROGRESSION DOWNSTREAM AROUND THE NORTHERN HIGH  
PLAINS RIDGE AXIS TO THE TROUGH OVER THE NORTHEAST CONUS. HOWEVER,  
LITTLE QPF DIFFERENCE IS NOTED BETWEEN THE 12Z GFS AND THE REST OF  
THE 12Z CONSENSUS, SO A GENERAL MODEL BLEND IS RECOMMENDED.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
JACKSON  
 
 
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