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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1830Z Dec 09, 2017)
 
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Abbreviations and acronyms used in this product
 
Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EST SAT DEC 09 2017

VALID DEC 09/1200 UTC THRU DEC 13/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
  
12Z MODEL PREFERENCES AND CONFIDENCE INTERVALS 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
ERRORS WITHIN THE GFS/NAM INITIALIZATIONS DO NOT SEEM TO DEGRADE
THEIR SHORT RANGE FORECASTS. 
  
 
SYSTEM SIDESWIPING THE PACIFIC NORTHWEST MONDAY AFTERNOON 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/UKMET/CANADIAN BLEND; CONFIDENCE AVERAGE

THE 12Z GFS/TO SOME DEGREE THE 12Z NAM WAS QUICKER THAN THE OTHER
GUIDANCE MOVING THIS SYSTEM THROUGH WESTERN CANADA INTO ALBERTA BY
LATE TUESDAY.  THE 00Z ECMWF/ITS ENSEMBLE MEAN LOOK TOO
STRONG/SLOW WITH THE SYSTEM THEY MAINTAIN AS A CLOSED LOW MOVING
OVER THE TOP OF THE RIDGE -- IT SHOULD END UP WEAKER DUE TO THE
SUPERGEOSTROPHIC FLOW IN THE REGION.  IT SHOULD PROBABLY MOVE ON A
MORE NORTHERLY TRAJECTORY AS WELL BASED ON THE POSITION OF THE
NORTHERNMOST EXTENT OF THE RIDGE NORTH OF AK.  A COMPROMISE OF THE
12Z ECMWF, 12Z UKMET, AND 12Z CANADIAN IS PREFERRED TO TAKE CARE
OF THE ECMWF ISSUE WITH AVERAGE CONFIDENCE.


UPPER LOW PARKING ACROSS NORTHWEST MEXICO MONDAY ONWARD
SECOND STRONGER CLIPPER MOVING ACROSS GREAT LAKES MON/TUE
CLIPPER DIVING INTO THE UPPER MIDWEST SUNDAY
SYSTEM MOVING BY THE NORTHEAST TODAY/SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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 TO DEAL WITH LINGERING DETAIL ISSUES WITH
ABOVE AVERAGE CONFIDENCE.


THE NEXT COMPLETE MODEL DIAGNOSTIC DISCUSSION (PMDHMD) WILL BE
ISSUED BY 1645Z SUNDAY. 

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