633  
FXUS10 KWNH 140753  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
352 AM EDT WED AUG 14 2019  
 
VALID AUG 14/0000 UTC THRU AUG 17/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z FINAL MODEL EVALUATION WITH PRELIMINARY PREFERENCES AND  
CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z GFS/00Z UKMET/00Z ECMWF AND ECMWF/GEFS ENSEMBLE  
MEANS  
CONFIDENCE: SLIGHTLY BELOW AVERAGE  
 
07Z UPDATE: THE MODEL TRENDS NOTED EARLIER REMAIN, AND ALTHOUGH  
THE UKMET CONTINUES TO HAVE A WARM BIAS WITH ITS MID-LEVEL  
HEIGHTS, IT HAS VERY MUCH A SIMILAR PATTERN AND EVOLUTION TO THE  
GFS/ECWMF.  
 
PREVIOUS DISCUSSION:  
THE GENERAL SYNOPTIC EVOLUTION REMAINS IN VERY GOOD AGREEMENT THAT  
A RIDGE IN THE WEST AND TROUGH IN THE EAST WILL TRANSITION TO  
BROAD CYCLONIC FLOW WITH A WEAK TROUGH OR NEAR ZONAL FLOW ACROSS  
MUCH OF THE CONUS. OVERALL THE GUIDANCE IS IN BETTER AGREEMENT  
THAN THE PAST SEVERAL NIGHTS, WITH SMALL SCALE FEATURES CREATING  
THE LARGEST DISCREPANCIES OVER THE FORECAST PERIOD.  
 
THE CMC REMAINS THE FASTEST WITH SHORTWAVES ROTATING THROUGH THE  
QUICK FLOW ACROSS THE NORTHERN TIER, REALLY FASTER THAN ANY OTHER  
AVAILABLE GUIDANCE AND OUTSIDE THE ENSEMBLE ENVELOPE. THE NAM IS  
ALSO FAST, BUT NOT NEARLY TO THE CMC SPEEDS, AND WITHIN THE  
ENVELOPE WHICH COULD MAKE IT USABLE. HOWEVER, THE NAM IS IN  
GENERAL TOO DEEP WITH EACH SHORTWAVE WHICH IMPACTS THE QPF  
BULL'S-EYES ACROSS THE CONUS.  
 
OF THE PREFERRED BLEND, EACH MODEL HAS IT'S SMALL DISCREPANCIES,  
BUT NOT SO MUCH TO MAKE THEM UNUSABLE. THE UKMET CONTINUES ITS  
TREND OF BEING TOO HIGH WITH HEIGHTS ACROSS THE CONUS, WHILE THE  
ECMWF IS A BIT WEAK WITH DUAL SHORTWAVES MOVING ACROSS THE ROCKIES  
AND CENTRAL PLAINS. THIS LEAVES THE GFS AS THE MOST RELIABLE MODEL  
AND SHOULD BE WEIGHTED THE MOST HEAVILY IN THE BLEND, BUT WILL  
CONTINUE TO INCLUDE A HEAVY PORTION OF THE ECENS AND GEFS MEANS AS  
WELL, BOTH FOR CONTINUITY AND TO REMOVE SOME OF THE UNCERTAINTY IN  
THE SMALLER SCALE.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
WEISS  
 

 
 
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