989  
FXUS10 KWNH 310644  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 AM EDT WED JUL 31 2019  
 
VALID JUL 31/0000 UTC THRU AUG 03/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION AND FINAL PREFERENCES/CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERVIEW OF THE CONUS FEATURES
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: AVERAGE  
   
..07Z UPDATE
 
 
ENOUGH NUDGES WERE MADE WITH THE 00Z UKMET/CMC CONCERNING  
MID-LEVEL VORTICITY THURSDAY INTO FRIDAY TOWARD THE REMAINING  
MODEL CONSENSUS TO INCLUDE THEM AS PART OF THE PREFERENCE. LITTLE  
CHANGES WERE NOTED WITH THE 00Z ECMWF COMPARED TO ITS PREVIOUS 12Z  
CYCLE. THEREFORE, A GENERAL MODEL BLEND IS RECOMMENDED.  
   
..PREVIOUS DISCUSSION FOLLOWS
 
 
MID-UPPER LEVEL TROUGHING WILL REMAIN ON EITHER SIDE OF A NEARLY  
STATIONARY RIDGE CENTERED OVER NM THROUGH SATURDAY MORNING. A  
TROUGH LOCATED EAST OF THE MISSISSIPPI RIVER HAS TWO COMPONENTS,  
ONE OVER SOUTHEASTERN CANADA AND A SOUTHERN PORTION NEAR THE  
CENTRAL GULF COAST INTO THE GULF OF MEXICO, WITH FORECASTS SHOWING  
SLOW EASTWARD PROGRESSION WITH THE NORTHERN STREAM COMPONENT.  
MEANWHILE, A CLOSED LOW JUST WEST OF THE BRITISH COLUMBIA COAST  
WILL SLOWLY MOVE INLAND WEDNESDAY NIGHT WHILE A SECOND  
SHORTWAVE/SMALL CLOSED LOW WILL STRENGTHEN TO ITS SOUTHWEST AND  
NEAR THE COASTS OF WASHINGTON THURSDAY NIGHT.  
 
THERE IS DECENT AGREEMENT WITH THE LARGE SCALE FEATURES ACROSS THE  
CONUS BUT THE 12Z CMC IS SIGNIFICANTLY SLOWER WITH A SHORTWAVE,  
WHICH ORIGINATES ACROSS THE SOUTHWEST TODAY, AS IT TRACKS AROUND  
THE SOUTHWESTERN RIDGE INTO THE GREAT PLAINS. AMONG THE REMAINING  
00Z NAM, 00Z GFS, 12Z ECWMF AND 12Z UKMET, THE 12Z UKMET HAS SOME  
DIFFERENCES WITH ITS HANDLING OF THE MID-LEVEL SHORTWAVE OVER THE  
MIDWEST FRIDAY INTO SATURDAY. SOME NORTH/SOUTH DIFFERENCES  
CONTINUE WITH A SURFACE LOW IN KANSAS AND OKLAHOMA, BUT ENSEMBLE  
SPREAD IS A BIT LARGER TODAY BEYOND 12Z/02 WHICH LOWERS CONFIDENCE  
SOMEWHAT. WHILE AGREEMENT OUTSIDE OF THE 12Z CMC IS RELATIVELY  
GOOD, THE 12Z ECMWF, 00Z NAM AND 00Z GFS SHOW THE BEST AGREEMENT  
WITH THE ENSEMBLES AND THEIR PREVIOUS RUNS.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
OTTO  
 

 
 
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