037  
FXUS10 KWNH 201717  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
116 PM EDT TUE AUG 20 2019  
 
VALID AUG 20/1200 UTC THRU AUG 24/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z INITIAL MODEL EVALUATION...INCLUDING PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL DETERMINISTIC MODEL BLEND  
CONFIDENCE: AVERAGE  
 
GUIDANCE IS IN GENERALLY GOOD AGREEMENT ON THE MAIN SYNOPTIC  
FEATURES THROUGH THURSDAY WHICH ARE THE LOW OVER NORTHERN ONTARIO  
SWINGING ACROSS QUEBEC AND THE PROGRESSIVE TROUGH FROM A LOW  
MOVING INTO SOUTHEAST ALASKA TONIGHT THAT SHIFTS ACROSS THE  
CANADIAN PRAIRIES AND NORTHWEST U.S. AS FLOW BECOMES ZONAL OVER  
THE PACIFIC NORTHWEST AND SOUTHWEST CANADA TO END THE WORK WEEK.  
TIMING AND MAGNITUDE DIFFERENCES GROW LARGE ON DAY 3 WITH THE  
ORIENTATION OF THE TROUGH OVER THE CANADIAN PRAIRIES INTO THE  
NORTHERN GREAT PLAINS AND THE LOW APPROACHING LABRADOR AND  
ASSOCIATED TROUGH CROSSING THE NORTHEASTERN U.S.  
 
SHORTWAVE ACTIVITY ALONG THE COLD FRONT OVER THE CENTRAL AND  
EASTERN U.S. HAS UNDERSTANDABLE VARIABILITY THOUGH PRECIPITATION  
FROM DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT OUTSIDE OF THE  
12Z NAM ON DAY 3 WHICH IS MUCH MORE ROBUST OVER NORTHERN MO.  
THEREFORE A GENERAL MODEL BLEND IS RECOMMENDED WITH A CAUTION OF  
THE 12Z NAM ON DAY 3.  
 
A TROUGH OF TROPICAL ORIGINS SHIFTS NORTH ACROSS THE WESTERN GULF  
OF MEXICO WITH POTENTIALLY HEAVY PRECIP ON THE NORTHERN END OF THE  
TROUGH REACHING THE LOUISIANA COAST ON FRIDAY. A GENERAL MODEL  
BLEND IS SUGGESTED WITH THIS FEATURE.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
JACKSON  
 

 
 
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