992  
FXUS10 KWNH 061657  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1257 PM EDT TUE AUG 06 2019  
 
VALID AUG 06/1200 UTC THRU AUG 10/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH INITIAL PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND, LESS WEIGHT ON 12Z UKMET AND 00Z  
CMC  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
A RIDGE IN THE WEST WILL EVENTUALLY MIGRATE WEST OVER THE NEXT  
COUPLE DAYS MAKING ROOM FOR AN APPROACHING TROUGH ALONG THE WEST  
COAST. MEANWHILE, MID-LEVEL VORTICITY WILL HELP TO  
ERODE/DEAMPLIFY THE UPPER RIDGE ACROSS THE NORTHERN ROCKIES. ALONG  
THE EAST COAST, TROUGHING CONTINUES AS MID-LEVEL ENERGY ROUNDS  
ANOTHER CLOSED LOW MOVING INTO ONTARIO.  
 
OVERALL MODEL GUIDANCE IS IN FAIRLY DECENT AGREEMENT IN TERMS OF  
MASS FIELDS WITH LIMITED SPREAD. HOWEVER, THERE ARE SOME ODDITIES  
WITH THE UKMET/CMC AS NOTED BY THE MID/UPPER LEVEL FLOW PATTERN,  
ESPECIALLY ASSOCIATED WITH THE TROUGH APPROACHING THE WEST COAST  
AND TROUGHING IN THE EAST. ALSO, MID-LEVEL ENERGY ROUNDING THE  
RIDGING AXIS ACROSS THE ROCKIES INTO THE PLAINS WILL HELP TO LOWER  
THE HEIGHTS AND THUS DEAMPLIFY THE PATTERN. THIS MAKES SENSE WITH  
THE 12Z NAM/GFS AND 00Z ECMWF ON BOARD. HOWEVER, THE 12Z UKMET  
AND THE 00Z CMC DOES NOT ILLUSTRATE THESE FEATURES. WHEN LOOKING  
AT THE QPF, THIS COULD LEAD TO SOME ISSUES.  
 
WHILE A GENERAL MODEL BLEND IS PREFERRED, THERE ARE DIFFERENCES  
WITH MID-LEVEL ENERGY PLACEMENT WHICH HINGES ON THE RIDGE AND  
TROUGH AXIS IN THE EAST. THE 12Z GFS IS FARTHER SOUTH ON DAY 3  
WHICH WOULD HAVE IMPLICATIONS IN TERMS OF QPF. HOWEVER,  
CONTINUITY HAS SHOWN THESE TYPE OF FEATURES TO MIGRATE FARTHER  
SOUTH IN TIME. THEREFORE, KEPT IT IN THE MODEL BLEND FOR NOW GIVEN  
IT IS NOT OUT OF TOLERANCE WITH THE MODEL/ENSEMBLE SPREAD. AND AS  
PREVIOUSLY MENTIONED, THE WETTER GFS SOLUTION IN THE WEST  
CONTINUES TO MAKE SENSE GIVEN THE CONSIDERABLE NORTHWARD PUSH OF  
MOISTURE AND AVAILABLE JET DYNAMICS FOR LARGE SCALE ASCENT.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
PAGANO  
 

 
 
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