976  
FXUS10 KWNH 041839  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
238 PM EDT SAT NOV 04 2017  
 
VALID NOV 04/1200 UTC THRU NOV 08/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL PREFERENCES WITH CONFIDENCE INTERVALS  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT  
RANGE FORECASTS.  
 
DEEP CYCLONE OFFSHORE THE PACIFIC NORTHWEST TUESDAY  
UPPER TROUGH MOVING BY FLORIDA SATURDAY/SUNDAY  
SHORTWAVE MOVING THROUGH NEW ENGLAND SUNDAY  
...SHORTWAVE MOVING FROM MT TODAY INTO QUEBEC BY MONDAY MORNING  
TRAILING COLD FRONT ACROSS THE GREAT LAKES INTO THE SRN PLAINS...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. A  
COMPROMISE OF THE 00Z ECMWF, 00Z UKMET, 00Z CANADIAN, 12Z GFS, AND  
12Z NAM IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.  
 
POSITIVELY TILTED TROUGH MOVING ACROSS THE WEST  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: MODEL BLEND; CONFIDENCE AVERAGE  
 
THE 12Z ECMWF, ITS 00Z ENSEMBLE MEAN, AND THE 12Z UKMET ARE SLOW  
OUTLIERS WITH THIS SYSTEM WHEN COMPARED TO THE 12Z GFS/GEFS, 12Z  
NAM, 09Z SREF MEAN, AND 12Z CANADIAN. AS A STRONG UPSTREAM RIDGE  
EXISTS, IMPLYING THE TROUGH WOULD DIG IN, IMPLYING A MORE  
SOUTHERLY SOLUTION COULD MATERIALIZE, WOULD HESITATE TO GO WITH  
THE MORE NORTHWESTERLY GUIDANCE. A COMPROMISE OF THE AVAILABLE  
GUIDANCE IS PREFERRED MASS FIELD-WISE WITH CONFIDENCE NO BETTER  
THAN AVERAGE. FOR QPF PREFERENCES, CONSULT THE WPC QPF/WINTER  
WEATHER DISCUSSIONS.  
 
WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ROTH  

 
 
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