473  
FXUS10 KWNH 121656  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1255 PM EDT THU MAR 12 2020  
 
VALID MAR 12/1200 UTC THRU MAR 16/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
...NORTHERN STREAM TROUGH TRACKING FROM THE UPPER MIDWEST TOWARD  
THE NORTHEAST THROUGH FRIDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE MODELS SHOW SIMILARLY WITH THIS SYSTEM.  
 
   
..CLOSED LOW DEVELOPING OVER PACIFIC NW FRIDAY/SATURDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON 12Z NAM BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE 12Z NAM REMAINS A BIT OF AN OUTLIER WITH RESPECT TO ITS CLOSED  
LOW DROPPING SOUTH ACROSS THE NORTHWEST U.S. THE NAM IS SLIGHTLY  
DEEPER AT 700 MB OFFSHORE AND LESS DEFINED WITH A LOW LEVEL  
CONVERGENCE AXIS OVER WEST-CENTRAL MT SATURDAY MORNING. THE  
DIFFERENCES IN STRENGTH EVEN OUT INTO SATURDAY NIGHT AND SUNDAY  
OFF OF THE WEST COAST, BUT THE TIMING OF THE NAM LAGS THE  
REMAINING MODEL CONSENSUS WITH ONLY WEAK ENSEMBLE SUPPORT. THE  
REMAINING NON-12Z NAM GUIDANCE LOOKS SIMILAR WITH THE CLOSED LOW  
FROM 850-300 MB ON SATURDAY AND SUNDAY.  
 
...CLOSED LOW TRACKING THROUGH THE SOUTHWEST AND WEAKENING ACROSS  
THE GREAT PLAINS THROUGH SATURDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
SOME RELATIVELY MINOR DIFFERENCES AS THE CLOSED LOW EJECTS  
EASTWARD AND WEAKENS THROUGH THE GREAT PLAINS. THE 00Z CMC WAS  
NOTED TO BE SLOWER AND A BIT DEEPER WITH THE REMNANT SHORTWAVE  
TROUGH AXIS, WHILE THE 12Z NAM WAS SLIGHTLY FASTER. OVERALL, MODEL  
SPREAD IS SMALL ENOUGH TO ALLOW FOR A GENERAL MODEL BLEND.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
OTTO  
 

 
 
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