562  
FXUS10 KWNH 101839  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
139 PM EST SUN DEC 10 2017  
 
VALID DEC 10/1200 UTC THRU DEC 14/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL PREFERENCES WITH CONFIDENCE INTERVALS  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT  
RANGE FORECASTS.  
 
 
CLOSED LOW STUCK ACROSS NORTHWEST MEXICO MONDAY-WEDNESDAY  
DEEP LAYER CYCLONE OVER NEW ENGLAND  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. A  
COMPROMISE OF THE 12Z GFS, 12Z NAM, 12Z ECMWF, 12Z UKMET, AND 12Z  
CANADIAN IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.  
 
CYCLONE/SHORTWAVE DIVING INTO THE MIDWEST LATE WEDNESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: WEAKER THAN 12Z ECMWF; CONFIDENCE AVERAGE  
 
THERE ARE DETAIL ISSUES AT 500 HPA WITH THE SHORTWAVES ROUNDING  
THE WEST SIDE OF THE TROUGH. THE 12Z ECMWF AND 12Z UKMET ARE  
LIKELY TOO STRONG CONSIDERING THE BREADTH OF THE UPPER TROUGH  
WHICH SHOULD ALLOW MINIMAL AMPLITUDE. THESE ISSUES MANIFEST  
THEMSELVES A BIT MORE IN THE LOW LEVELS, WITH THE 12Z UKMET THE  
FARTHEST NORTH AND THE CANADIAN THE FARTHEST SOUTHWEST. BOTH LIE  
OUTSIDE THE 00Z ENSEMBLE LOW SPREAD SO ARE NOT CONSIDERED VIABLE.  
A COMPROMISE OF THE 12Z NAM, 12Z GFS, AND 12Z ECMWF SHOULD DEAL  
WITH THE ECMWF'S DEPTH ISSUE ALOFT EFFECTIVELY AND REMAIN WITHIN  
THE ENSEMBLE SPREAD AT THE SURFACE. CONFIDENCE IS AVERAGE IN THIS  
CHOICE.  
 
THE NEXT COMPLETE MODEL DIAGNOSTIC DISCUSSION (PMDHMD) WILL BE  
ISSUED BY 1645Z MONDAY.  
 
ROTH  
 
PREVIOUS MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
 
PREVIOUS 500 MB FORECASTS AT  
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 

 

 
 
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