105  
FXUS10 KWNH 061630  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1229 PM EDT FRI SEP 06 2019  
 
VALID SEP 06/1200 UTC THRU SEP 10/0000 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 THROUGH DAY 2; NON-GFS NORTHERN  
PLAINS DAY 3  
CONFIDENCE:  
 
THE INITIAL 12Z GUIDANCE OFFERS FAIRLY GOOD AGREEMENT THROUGH 48  
HOURS ACROSS THE CONUS. THE MAIN FEATURES OF INTEREST WILL  
SHORTWAVES ACROSS THE NORTHERN TIER, ONE OF WHICH WILL INTERACT  
WITH HURRICANE DORIAN AS IT BECOMES EXTRATROPICAL (MORE DETAILS  
BELOW). ANOTHER SHORTWAVE WILL PUSH INTO THE NORTHERN PLAINS ON  
SUNDAY WHERE THERE IS TIGHT CLUSTERING BETWEEN THE MODELS WITH  
RESPECT TO THE MASS FIELDS. LARGER DIFFERENCES BECOME APPARENT BY  
DAY 3, MAINLY ACROSS THE WESTERN U.S. AND NORTHERN PLAINS WITH THE  
NEXT (STRONGER) SHORTWAVE. WITH RIDGING UPSTREAM OVER THE UPPER  
MIDWEST EARLY NEXT WEEK, THE NEXT SHORTWAVE COMES OUT OF THE  
NORTHERN ROCKIES. THE GFS IS A FLATTER, MORE OPEN SOLUTION THAT  
SUBSEQUENTLY IS FURTHER EAST WITH ITS LOW POSITION AND QPF FIELDS.  
THE OTHER GUIDANCE MEMBERS ARE MORE AMPLIFIED WITH THE SHORTWAVE,  
WITH THE LOW FURTHER WEST OVER MONTANA. LOOKING AT THE NON-NCEP  
GUIDANCE AND THE 06Z GEFS, IT APPEARS THE 12Z GFS MIGHT BE TOO  
MUCH OF AN OUTLIER TO INCLUDE, ESPECIALLY FOR ITS QPF, AT THIS  
TIME. OTHERWISE, THROUGH DAY 2, A GENERAL MODEL BLEND CAN BE  
APPLIED.  
 
   
..HURRICANE DORIAN
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PLEASE REFER TO THE OFFICIAL NATIONAL HURRICANE CENTER FORECAST  
TRACK. WITH THE LATEST (15Z) NHC ADVISORY, THERE IS GOOD AGREEMENT  
WITH THE LATEST MODEL SUITE THROUGH 48 HOURS AS DORIAN CONTINUES  
NORTHEAST AND BEGINS EXTRATROPICAL TRANSITION, INTERACTING WITH AN  
APPROACHING SHORTWAVE TROUGH FROM THE GREAT LAKES REGION. A  
MULTI-MODEL CONSENSUS PROVIDES A GOOD PROXY FOR THE OFFICIAL  
TRACK, WITH SUBTLE DIFFERENCES SEEN IN THE LATEST MODELS (GFS  
WEST, NAM EAST) BUT OVERALL THERE IS TIGHT CLUSTERING THROUGH 60  
HOURS.  
 
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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