925  
FXUS10 KWNH 270425  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1224 AM EDT MON JUL 27 2020  
 
VALID JUL 27/0000 UTC THRU JUL 30/1200 UTC  
 
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..MID-UPPER LEVEL TROUGHING OVER THE NORTHERN CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
MID TO UPPER-LEVEL ENERGY OVER SOUTHERN CANADA IS EXPECTED TO  
CLOSE OFF BEFORE SETTLING OVER ONTARIO LATER IN THE PERIOD, WHILE  
THE LARGER SCALE TROUGH DEEPENS OVER THE GREAT LAKES REGION. AT  
THE SURFACE, A PRONOUNCED COLD FRONT IS FORECAST TO MARCH ACROSS  
THE NORTHERN TIER INTO THE GREAT LAKES WHILE UPSTREAM RIDGING  
BUILDS OVER THE CANADIAN ROCKIES. IN THE INCREASINGLY AMPLIFIED  
PATTERN, THE MODELS HAVE CONVERGED ON A SIMILAR IDEA AND SHOW VERY  
GOOD AGREEMENT THROUGH 84 HOURS WITH THE SYNOPTIC PATTERN.  
 
   
..MID-LEVEL ENERGY OVER CALIFORNIA/GREAT BASIN
 
   
..ENERGY ADVANCING SOUTHEAST ACROSS THE PLAINS BY WEDNESDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH 60 HOURS; ECMWF/GFS BLEND  
AFTER  
CONFIDENCE: AVERAGE  
 
A PIECE OF MID-LEVEL ENERGY OVER SOUTHERN/SOUTH-CENTRAL CALIFORNIA  
LIFTS THROUGH THE GREAT BASIN OVER THE NEXT COUPLE OF DAYS. AS IT  
REACHES THE ROCKIES AND INTO THE FRONT RANGE, IT AMPLIFIES AS  
HEIGHTS BUILD UPSTREAM AND TROUGHING SETTLES OVER THE GREAT LAKES.  
THE NAM IS THE FASTEST TO EJECT THE ENERGY INTO THE CENTRAL PLAINS  
WHILE THE CMC BOTTLES IT UP BACK OVER WYOMING THROUGH THE PERIOD.  
THE UKMET ALSO AMPLIFIES THE RIDGE TOO MUCH, SO THE MODEL  
PREFERENCE IS FOR A BLEND OF THE GFS/ECMWF, BEYOND 60 HOURS.  
 
   
..SHORTWAVE TROUGHS APPROACHING CA/PACIFIC NORTHWEST
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-UKMET BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
MODELS HAVE COME INTO SLIGHTLY BETTER AGREEMENT WITH THE  
DEVELOPMENT OF A LARGE CLOSED LOW WELL OFFSHORE THE PACIFIC  
NORTHWEST LATE IN THE FORECAST PERIOD. WITH THE INCREASINGLY  
AMPLIFIED PATTERN CHARACTERIZED BY RIDGING ANCHORED OVER THE GREAT  
BASIN INTO THE INTERIOR WEST, THE UPPER LEVEL LOW UPSTREAM STALLS  
AND DEEPENS. THE MODELS HAVE CONVERGED ON A SIMILAR SYNOPTIC  
PATTERN AND NO REAL SIGNIFICANT ISSUES IN THE MASS FIELDS WERE  
NOTED. A GENERAL MODEL BLEND IS PREFERRED.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
THIS PRODUCT WILL TERMINATE AUGUST 15, 2020:  
WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.  
PDF  
 
TAYLOR  
 

 
 
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