285  
FXUS10 KWNH 050644  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 AM EDT MON AUG 05 2019  
 
VALID AUG 05/0000 UTC THRU AUG 08/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
---06Z UPDATE---  
NO SIGNIFICANT CHANGE TO THE PRELIMINARY PREFERENCE. THE 00Z NAM  
IS MORE AMPLIFIED WITH THE TROUGH IN THE EAST THIS WEEK THAN OTHER  
MODELS, AND THE REMAINING GLOBAL MODELS ARE NOW MORE CLOSELY  
CLUSTERED AROUND A LESS AMPLIFIED SCENARIO. THEREFORE, LESS WEIGHT  
WILL BE PLACED ON THE NAM BY MID-WEEK.  
 
---PREVIOUS DISCUSSION---  
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.  
 
OVER THE PAST COUPLE MODEL CYCLES, THE NAM AND UKMET HAVE COME  
INTO BETTER AGREEMENT WITH THE OTHER DETERMINISTIC MODELS AND  
ENSEMBLE MEANS. THESE TWO MODELS WERE EXCLUDED FROM THE MODEL  
PREFERENCE PREVIOUSLY, BUT ARE NOW SIMILAR WITH THE LARGE SCALE  
PATTERN. A BROADER MODEL BLEND IS PREFERRED.  
 
WITH RESPECT TO THE FORECAST QPF, GREATEST WEIGHT WAS PLACED ON  
THE GFS AND ECMWF, WHICH OFFERED RELATIVELY CONSISTENT FORECASTS.  
AND SLIGHTLY MORE WEIGHT WAS PLACED ON THE GFS AS COMPARED TO THE  
ECMWF, AS IT SHOWED MORE SIGNIFICANT MCS ACTIVITY ON THE PERIPHERY  
OF THE RIDGE IN THE PLAINS, AND SHOWED MORE SUBSTANTIAL QPF IN THE  
WEST ASSOCIATED WITH A NORTHWARD PUSH OF MOISTURE AND FAVORABLE  
JET STREAM DYNAMICS.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
LAMERS  
 

 
 
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