583   
FXUS10 KWNH 021858  
PMDHMD  
  
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
257 PM EDT WED OCT 02 2019  
  
VALID OCT 02/1200 UTC THRU OCT 06/0000 UTC  
  
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
  
12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
  
19Z UPDATE: NO SIGNIFICANT CHANGES NOTED WITH THE REST OF THE 12Z  
GUIDANCE. THE ECMWF CAME IN A BIT MORE AMPLIFIED WITH THE  
APPROACHING TROUGH ON DAY 3 IN THE NORTHWEST AND NORTHERN ROCKIES,  
BUT ITS DIFFERENCES WERE NOT SIGNIFICANT ENOUGH TO NOT INCLUDE.  
THE UKMET TRENDED SLOWER AND NOW IS MORE ALIGNED WITH THE REST OF  
THE GUIDANCE, SO IT CAN BE INCORPORATED MORE ON DAY 3. WITH THIS  
IN MIND, A GENERAL MODEL BLEND CAN BE APPLIED THROUGH ALL 3 DAYS.  
  
---PREVIOUS DISCUSSION---  
RELATIVELY GOOD AGREEMENT IN THE MODEL GUIDANCE THROUGH DAY 2  
ACROSS THE CONUS. THE SYNOPTIC PATTERN IS EXPECTED TO TRANSITION  
TO MORE ZONAL FLOW AS THE HIGHLY AMPLIFIED TROUGH WEST / RIDGE  
EAST PATTERN BREAKS DOWN. BY DAY 3, ANOTHER LONGWAVE TROUGH IS  
EXPECTED TO MOVE ONSHORE THE PACIFIC NORTHWEST AND THEN ACROSS THE  
INTERIOR NORTHERN ROCKIES. THIS IS WHERE THE GREATEST MODEL  
DIFFERENCES ARE NOTED.  
  
THE 00Z UKMET IS THE BIGGEST OUTLIER COMPARED TO THE REST OF THE  
DETERMINISTIC AND ENSEMBLE GUIDANCE. ITS TROUGH AXIS IS MORE  
NEGATIVELY TILTED AND FASTER (BRINGING ITS AXIS THROUGH ND BY DAY  
3). ALSO THE 12Z NAM IS A BIT FASTER AND MORE AMPLIFIED. THERE IS  
RELATIVELY GOOD AGREEMENT BETWEEN THE ECMWF/CMC/GFS ON AXIS AND  
POSITION THROUGH DAY 3 AND HAS SUPPORT FROM ASSOCIATED ENSEMBLE  
MEMBERS. ELSEWHERE ACROSS THE CONUS, SURFACE HIGH PRESSURE WILL  
GENERALLY DOMINATE THE EASTERN US WHILE BY THE END OF DAY 3,  
SOUTHERLY RETURN AND SURFACE CYCLOGENESIS TAKES PLACE IN THE  
CENTRAL PLAINS.  
  
WITH THE ABOVE AVERAGE CONSISTENCY AND MODEL PATTERN THROUGH DAY  
2, A GENERAL MODEL BLEND CAN BE APPLIED. FOR DAY 3, AND  
SPECIFICALLY THE NORTHWEST AND INTERIOR NORTHERN ROCKIES, MORE  
WEIGHT/INCLUSION OF THE ECMWF/CMC/GFS IS PREFERRED.  
  
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
  
TAYLOR  
  
  
 
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