419  
FXUS10 KWNH 141700  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1259 PM EDT SAT MAR 14 2020  
 
VALID MAR 14/1200 UTC THRU MAR 18/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z FINAL MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERVIEW OF SYSTEMS AFFECTING THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE UPPER PATTERN ACROSS THE LOWER 48 WILL BE QUASI-AMPLIFIED IN  
THE SHORT RANGE WITH HIGHLY MERIDIONAL FLOW ALONG THE WEST COAST  
OF NORTH AMERICA AND ZONAL FLOW OVER THE EASTERN 2/3 OF THE  
NATION...AT LEAST EARLY ON. BY MONDAY, A LONGWAVE TROUGH WILL  
BEGIN TO SWEEP ACROSS THE NORTH-CENTRAL U.S./GREAT LAKES REGION  
INTO THE MIDDLE OF THE WEEK.  
 
THERE WERE SOME MINOR DIFFERENCES WITH A STRONG CLOSED LOW  
DROPPING SOUTH ALONG THE WEST COAST WITH THE 12Z NAM/GFS STRONGER  
WITH THE 850-500 MB LOW COMPARED TO THE 00Z ECMWF/UKMET/CMC. THE  
ENSEMBLE MEANS SPLIT THE DIFFERENCE IN STRENGTH. BY MONDAY  
EVENING, MINOR TIMING DIFFERENCES ARISE WITH THE 12Z NAM FASTEST  
WITH A LOBE OF ENERGY INTO THE SOUTHWEST, BRINGING THE CLOSED LOW  
TO THE EAST FASTER THAN A STRONG MAJORITY OF GUIDANCE. HOWEVER BY  
TUESDAY EVENING, THE DIFFERENCES IN TIMING ARE REDUCED AND SO A  
GENERAL MODEL BLEND APPEARS REASONABLE FOR THIS SYSTEM WITH  
PERHAPS LESS 12Z NAM INFLUENCE MONDAY INTO TUESDAY.  
 
UP NORTH, THE 12Z GFS CONTINUES TO BE SLIGHTLY FASTER WITH A  
LONGWAVE TROUGH AND ASSOCIATED COLD FRONT THROUGH THE NORTHERN  
U.S. THE 00Z ECMWF/UKMET CATCH UP WITH THE 12Z GFS BY LATER MONDAY  
THOUGH WITH PERHAPS THE 12Z NAM AND 00Z CMC LOOKING A BIT SLOW.  
THE DIFFERENCES IN TIMING ARE MORE OF AN IMPACT TO ONTARIO AND  
QUEBEC WITH RESULTING IMPACTS ACROSS THE U.S. RELATIVELY MINOR.  
 
OTHER SYSTEMS AFFECTING THE LOWER 48, INCLUDING A WEAKENING  
SHORTWAVE ACROSS THE MISSISSIPPI RIVER VALLEY TODAY AND A FRONTAL  
BOUNDARY ACROSS THE SOUTHERN U.S. SHOW RATHER GOOD AGREEMENT WITH  
MODEL MASS FIELDS, SUPPORTING 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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