169  
FXUS10 KWNH 050634  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
133 AM EST SUN NOV 05 2017  
 
VALID NOV 05/0000 UTC THRU NOV 08/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH FINAL PREFERENCES  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT  
RANGE FORECASTS.  
 
...SHORTWAVE TRACKING THROUGH ONTARIO TODAY AND QUEBEC ON MONDAY  
WITH TRAILING COLD FRONT EXTENDING FROM THE GREAT LAKES/NORTHEAST  
TO THE SOUTHERN PLAINS...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
ONLY MINOR TIMING DIFFERENCES EXIST WITH THE MID-LEVEL SHORTWAVE  
AND SURFACE COLD FRONT THROUGH MONDAY. SLOWER MODELS LIKE THE 12Z  
ECMWF SPED UP WITH MORE AGREEMENT/CONVERGENCE SEEN IN THE FULL 00Z  
MODEL SUITE CONCERNING THE COLD FRONT MOVING THROUGH THE OHIO  
VALLEY. GIVEN THE LATEST DIFFERENCES CONTINUE TO SHRINK...A  
GENERAL MODEL BLEND IS RECOMMENDED FOR THIS SYSTEM.  
 
...POSITIVELY TILTED TROUGH TRANSLATING FROM THE PACIFIC NORTHWEST  
TODAY TO THE CENTRAL ROCKIES BY TUESDAY EVENING...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z GFS/00Z ECMWF/00Z UKMET BLEND  
CONFIDENCE: AVERAGE  
 
THE 00Z NAM IS NOTICEABLY STRONGER AND SLOWER WITH THE NORTHERN  
REFLECTION OF THIS SHORTWAVE...WHICH IS EXPECTED TO MOVE THROUGH  
THE UPPER MIDWEST ON TUESDAY. GOOD AGREEMENT HERE FOR A NON-00Z  
NAM BLEND. REGARDING THE PORTION OF THE TROUGH OVER THE  
ROCKIES...THE LATEST ENSEMBLE SPAGHETTI PLOTS SHOW A FAIR DEGREE  
OF SPREAD WITH THE 12Z ECMWF MEAN LESS AMPLIFIED THAN THE 00Z/12Z  
ECMWF. REGARDING THE WEAKER GFS/GEFS...THE SIMILAR 00Z GEFS MEAN  
AND 00Z GFS AND 00Z UKMET MAKE UP THE SLIGHTLY WEAKER CAMP.  
MEANWHILE...THE 00Z CMC IS MUCH MORE PROGRESSIVE WITH THE TROUGH  
AXIS TOWARD THE SOUTH AND EAST...ON THE EDGE OF THE LATEST  
ENSEMBLE GUIDANCE AND A NEAR OUTLIER.  
 
THE END RESULT OF THESE DIFFERENCES IS FOR A PREFERRED SOLUTION IN  
THE MIDDLE...BETWEEN THE STRONGER AND WEAKER MODELS...WHICH IS A  
BLEND OF THE 00Z GFS/00Z ECMWF/00Z UKMET.  
 
...DEEP CYCLONE LOCATED OFFSHORE OF THE PACIFIC NORTHWEST BY  
WEDNESDAY MORNING...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z GFS...00Z NAM...00Z UKMET BLEND  
CONFIDENCE: AVERAGE  
 
OVERALL ENSEMBLE TRENDS HAVE BEEN FASTER TO BRING THE LARGE CLOSED  
LOW CLOSER TO SHORE OVER THE PAST 4 12Z/00Z CYCLES. WHILE 00Z  
DETERMINISTIC MODEL DIFFERENCES ARE NOT TOO LARGE..THE PREFERENCE  
IS TO STAY TOWARD THE MIDDLE TO FRONT EDGE OF THE LATEST  
DETERMINISTIC DIFFERENCES GIVEN ENSEMBLE TRENDS. THIS IS CLOSEST  
TO A 00Z NAM...00Z GFS AND 00Z UKMET BLEND. THE 00Z ECMWF AND 00Z  
CMC TRENDED MORE OFFSHORE...ESPECIALLY SEEN IN THE 00Z CMC  
COMPARED TO ITS 12Z RUN ON TUESDAY AND WEDNESDAY.  
 
   
..UPPER TROUGH DEPARTING FROM FLORIDA TODAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL COMPROMISE  
CONFIDENCE: AVERAGE  
 
THE MODELS SHOW SIMILARLY WITH THIS SYSTEM.  
 
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WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
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