226  
FXUS10 KWNH 130427  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1226 AM EDT FRI OCT 13 2017  
 
VALID OCT 13/0000 UTC THRU OCT 16/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PRELIMINARY MODEL PREFERENCES  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT  
RANGE FORECASTS.  
 
KICKER SHORTWAVE MOVING INTO THE GREAT LAKES MONDAY  
FRONT MOVING INTO THE GREAT LAKES/NORTHEAST FRIDAY/SATURDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
SINCE THERE REASONABLE MODEL AGREEMENT WITH THESE SYSTEMS, PREFER  
A COMPROMISE OF THE 12Z UKMET, 12Z ECMWF, 12Z CANADIAN, 00Z NAM,  
AND 00Z GFS WITH ABOVE AVERAGE CONFIDENCE.  
 
SYSTEM MOVING FROM THE NORTHWEST INTO THE GREAT LAKES SUNDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-NAM BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
BY SUNDAY MORNING, THE 00Z NAM BECOMES SLOW AND DEEP WITH THIS  
SYSTEM. THE GUIDANCE HAS BEEN TRENDING NORTHEAST, THE GENERAL  
FLOW PATTERN IS DEAMPLIFYING AT THAT POINT IN TIME, AND THE NAM'S  
SOLUTION FITS ITS USUAL BIAS AT THIS TIME RANGE, PREFER A  
COMPROMISE OF THE 00Z GFS, 12Z UKMET, 12Z CANADIAN, AND 12Z ECMWF  
WITH SLIGHTLY ABOVE AVERAGE CONFIDENCE.  
 
TROPICAL WAVE MOVING THROUGH THE FL STRAITS  
LINGERING UPPER TROUGH/UPPER LOW NEAR THE BAHAMAS INTO MONDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-UKMET BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE 12Z UKMET IS UNIQUELY WEAK WITH THIS SYSTEM OVER THE NEXT 84  
HOURS. WITH THE 18Z GEFS AND 12Z ECMWF ENSEMBLE MEAN SOLUTIONS  
SUPPORTING THE STRONGER CONSENSUS, PREFER A COMPROMISE OF THE 00Z  
NAM, 00Z GFS, 12Z UKMET, AND 12Z CANADIAN WITH SLIGHTLY ABOVE  
AVERAGE CONFIDENCE.  
 
WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ROTH  

 
 
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