999  
FXUS10 KWNH 100647  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
146 AM EST SUN NOV 10 2019  
 
VALID NOV 10/0000 UTC THRU NOV 13/1200 UTC  
 
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
   
..00Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
...AMPLIFYING MID-LEVEL TROUGH AXIS INTO THE NORTH-CENTRAL U.S.  
FOR MONDAY...   
..SURFACE LOW IN THE VICINITY OF NEW ENGLAND TUESDAY MORNING
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON 00Z UKMET BLEND  
CONFIDENCE: AVERAGE  
   
..07Z UPDATE
 
 
THE 00Z SUITE OF DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT NOW  
REGARDING THE SHORTWAVE TROUGH AND SURFACE LOW TRACK. WHILE THE  
00Z UKMET ADJUSTED FAVORABLY WITH RESPECT TO ITS PREVIOUS 12Z  
CYCLE, THE UKMET REMAINS A BIT MORE PROGRESSIVE AND OFFSHORE WITH  
THE SURFACE LOW NEAR NEW ENGLAND THAN IDEAL. A NON 00Z UKMET BLEND  
IS PREFERRED TO SMOOTH OUT REMAINING SMALLER SCALE DIFFERENCES.  
   
..PREVIOUS DISCUSSION FOLLOWS
 
 
THERE IS GOOD AGREEMENT WITH THE UPPER TROUGH AMPLITUDE AND TIMING  
AS IT NEARS THE GREAT LAKES REGION WITH MINOR DIFFERENCES SHOWING  
UP AFTER TUESDAY MORNING. THE 12Z UKMET IS FLATTER AND FASTER WITH  
THE SHORTWAVE, RESULTING IN AN EASTWARD DISPLACED SURFACE LOW  
EARLY TUESDAY. MEANWHILE, THE 12Z CMC BECOMES SLIGHTLY  
SLOWER/DEEPER WITH THE UPPER TROUGH PLACEMENT RESULTING IN A  
SURFACE LOW DISPLACED TO THE SOUTH A BIT OF THE AGREEABLE 00Z NAM,  
00Z GFS AND 12Z ECMWF.  
 
THE GOOD AGREEMENT WITH THE SURFACE LOW AMONG THE 00Z NAM/00Z  
GFS/12Z ECMWF IS BROKEN UP BY THE 18Z AND 12Z GEFS/12Z ECMWF MEAN  
SURFACE LOWS DISPLACED SLIGHTLY SOUTH AND EAST OF THE  
DETERMINISTIC CONSENSUS. THEREFORE, BLENDING THE NAM/GFS/ECMWF  
WITH THE 12Z ECMWF MEAN IS PREFERRED TO ACCOUNT FOR THE  
DISPLACEMENT OF THE MEANS RELATIVE TO THE DETERMINISTIC AGREEMENT.  
 
   
..COLD FRONT NEARING THE PACIFIC NORTHWEST ON TUESDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON 00Z UKMET BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
   
..07Z UPDATE
 
 
ENSEMBLE SPAGHETTI PLOTS AT 500 MB, SHOWING THE 546 DAM LINE  
INDICATE THE SOMEWHAT STRONGER 00Z ECMWF/CMC AND 00Z NAM MODELS  
ARE ON THE STRONGER EDGE OF THE MAJORITY OF MEMBERS. HOWEVER, THE  
RUN TO RUN CONSISTENCY OF THE ECMWF AND CMC CAN'T BE IGNORED. FOR  
NOW, A BLEND OF THE SOMEWHAT FLATTER 00Z GFS WITH THE MORE ROBUST  
00Z ECMWF/CMC IS PREFERRED WITH THE 00Z UKMET FASTER AND FLATTER  
AT 500 MB.  
   
..PREVIOUS DISCUSSION FOLLOWS
 
 
COLD FRONTAL TIMING INTO THE PACIFIC NORTHWEST IS GOOD WITH THE  
LATEST GUIDANCE. DIFFERENCES SHOW UP WITH THE CORRESPONDING  
SHORTWAVE DOWNSTREAM INTO THE NORTH-CENTRAL U.S. THE 12Z CMC  
STANDS OUT WITH A STRONGER/FASTER SHORTWAVE WHILE THE 12Z UKMET IS  
WEAKER BY 12Z/13. A BLEND OF THE 00Z NAM, 12Z ECMWF AND 00Z GFS IS  
REASONABLE GIVEN BETTER AGREEMENT TO THE ENSEMBLE MEANS.  
 
   
..CLOSED LOW OVER NORTHWESTERN MEXICO
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON 00Z UKMET BLEND  
CONFIDENCE: AVERAGE  
   
..07Z UPDATE
 
 
ONLY THE 00Z UKMET REMAINS AS A FASTER OUTLIER REGARDING THE 500  
MB LOW TRACK ACROSS NORTHWESTERN MEXICO. STRONG ENSEMBLE SUPPORT  
FOR A SLOWER, NON-UKMET TRACK, LEAVES THE 00Z UKMET AN UNLIKELY  
PICK FOR THIS SYSTEM. THE PREFERENCE IS FOR A NON-00Z UKMET BLEND.  
   
..PREVIOUS DISCUSSION FOLLOWS
 
 
ENSEMBLE SPREAD IS MODEST BY 12Z/13 BUT THE 12Z CMC IS SLOWER AND  
12Z UKMET FASTER THAN THE MIDDLE OF THE SPREAD. THE MIDDLE OF THE  
SPREAD, TIGHTER CLUSTERING AND ENSEMBLE MEANS SUPPORTS A BLEND OF  
THE 00Z NAM, 00Z GFS AND 12Z ECMWF.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
OTTO  
 

 
 
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