740  
FXUS10 KWNH 030638  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
238 AM EDT FRI NOV 03 2017  
 
VALID NOV 03/0000 UTC THRU NOV 06/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH FINAL PREFERENCES  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
   
..UPPER TROUGH IN THE PACIFIC NORTHWEST TODAY
 
DEAMPLIFYING AND  
EJECTING INTO THE NRN PLAINS THIS WEEKEND...  
...ASSOCIATED COLD FRONT EXTENDING FROM THE GREAT LAKES TO THE SRN  
PLAINS BY MON MORNING...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF 00Z ECMWF/GFS/CMC  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
DESPITE TRENDING SLOWER...THE 00Z UKMET CONTINUES TO BE FASTER  
THAN THE LATEST DETERMINISTIC MODELS WITH THE SHORTWAVE TRACKING  
THROUGH S-CNTRL CANADA ON SATURDAY AND THE UKMET ALSO REMAINS  
TOWARD THE FASTER EDGE OF AVAILABLE ENSEMBLE GUIDANCE. DESPITE  
SOME FASTER TRENDS OVERALL IN THE ENSEMBLES SINCE YESTERDAY...THE  
00Z UKMET STANDS OUT ENOUGH TO DISCOUNT IT FROM THE PREFERENCE.  
THE 00Z NAM IS ON THE STRONGER SIDE OF THE MODEL GUIDANCE AND THE  
00Z GFS A BIT WEAKER REGARDING THE 500 MB REFLECTION OF THIS  
SYSTEM. HOWEVER...THE BEST ENSEMBLE MEAN AGREEMENT FAVORS A BLEND  
OF THE 00Z GFS WITH THE 00Z ECMWF AND 00Z CMC...WITH THE ECMWF/CMC  
RELATIVELY UNCHANGED FROM THEIR PREVIOUS CYCLES...WHICH HELPS  
INCREASE CONFIDENCE SOME IN THE PREFERENCE.  
 
...MID-UPPER LEVEL SHORTWAVE AMPLIFYING TOWARD THE PACIFIC  
NORTHWEST SATURDAY INTO SUNDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
MODEL AGREEMENT WITH THE MASS FIELDS FOR THIS SYSTEM IS FAIRLY  
GOOD BUT THERE ARE SOME TIMING DIFFERENCES WORTH NOTING BY MONDAY  
ACROSS THE WEST WITH THE 500 MB TROUGH AXIS. THE DETERMINISTIC  
MODELS HAVE BEEN TRENDING FASTER SINCE YESTERDAY BUT THE TREND IN  
THE ENSEMBLES HAS JUST BEEN TO BE A BIT WEAKER OVER THE PAST 4  
12Z/00Z CYCLES. WHILE THE 12Z/02 CMC STOOD OUT THE MOST WITH A  
MORE AMPLIFIED/SLOWER SOLUTION,,.IT TRENDED FASTER/WEAKER TOWARD  
THE REMAINING DETERMINISTIC CONSENSUS. THE 00Z ECMWF ALSO TRENDED  
A BIT FASTER WHILE NO SIGNIFICANT CHANGE WAS SEEN IN THE 00Z UKMET  
RELATIVE TO ITS 12Z RUN.  
 
THE END RESULT IS A FAIRLY SIMILAR EVOLUTION FROM THE 00Z  
DETERMINISTIC GUIDANCE WITH THE NAM/GFS A BIT FASTER THAN THE  
ECMWF/UKMET/CMC. BLENDING THE 00Z GUIDANCE LIES NEAR THE MIDDLE OF  
THE LATEST ENSEMBLE CLUSTERING.  
 
...UPPER LEVEL SHORTWAVE REACHING TX/OK THIS MORNING AND TRACKING  
EASTWARD THROUGH FRIDAY AND AMPLIFYING OVER FLORIDA ON SATURDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON 00Z NAM BLEND  
CONFIDENCE: AVERAGE  
 
THERE REMAINS SOME MINOR STRENGTH DIFFERENCES NOTED WITH THE  
MID-LEVEL REFLECTION OF THIS SYSTEM. THE 00Z NAM REMAINS TOWARD  
THE STRONGER SIDE OF THE MODELS IN THE LOW-MID LEVELS. A NON 00Z  
NAM BLEND SHOWS GOOD AGREEMENT AT THIS TIME WHICH IS REFLECTED IN  
THE PREFERENCE. THE 00Z ECMWF/UKMET/CMC ARE RELATIVELY UNCHANGED  
FROM THEIR PREVIOUS CYCLES.  
 
...SHORTWAVE CLIPPING NRN NEW ENGLAND TODAY WITH ASSOCIATED  
TRAILING COLD FRONT TO THE SOUTHWEST...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
ONLY MINOR TIMING DIFFERENCES ARE IN PLACE WITH THIS SYSTEM SUCH  
THAT A GENERAL MODEL BLEND CAN BE USED. NO SIGNIFICANT CHANGES  
WERE NOTED WITH THE 00Z ECMWF/UKMET/CMC RELATIVE TO THEIR PREVIOUS  
12Z CYCLES.  
 
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WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
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