238  
FXUS10 KWNH 060658  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
157 AM EST MON NOV 06 2017  
 
VALID NOV 06/0000 UTC THRU NOV 09/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH FINAL PREFERENCES  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
...COLD FRONT MOVING THROUGH THE NORTHEAST TODAY BUT STALLING OVER  
THE SOUTH TUE/WED...   
..FRONTAL LOW OVER THE TN VALLEY ON TUE
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF 00Z GFS / 00Z ECMWF  
CONFIDENCE: ABOVE AVERAGE  
 
GOOD MODEL AGREEMENT EXISTS WITH THE COLD FRONTAL PASSAGE ACROSS  
THE EAST COAST BUT SOME DIFFERENCES CONTINUE REGARDING A FRONTAL  
WAVE IN THE TN VALLEY BY TUE MORNING. THE 00Z NAM IS THE STRONGEST  
OF THE DETERMINISTIC MODELS WHILE THE 00Z UKMET IS A BIT WEAKER  
THAN THE CONSENSUS. ENSEMBLE SCATTER LOW PLOTS HAVE BEEN  
RELATIVELY CONSISTENT WITH A PLACEMENT IN E-CNTRL TN FOR 12Z/TUE.  
A BLEND OF THE 00Z GFS AND 00Z ECMWF APPEARS BEST FOR THIS SYSTEM  
THROUGH WEDNESDAY NIGHT AS THE LOW WEAKENS TOWARD THE EAST.  
 
...POSITIVELY TILTED TROUGH TRANSLATING FROM THE PACIFIC NORTHWEST  
TODAY TO THE PLAINS BY WEDNESDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z ECMWF/GFS BLEND  
CONFIDENCE: AVERAGE  
 
THE LATEST ENSEMBLE TRENDS SHOW DEEPER WITH THE TROUGH ACROSS THE  
WRN U.S. BY TUE EVENING...BUT THE 00Z DETERMINISTIC TRENDS ARE  
LESS CONSISTENT. THE 00Z CMC CONTINUES TO APPEAR TOO FAST WITH THE  
UPPER TROUGH AS IT MOVES INTO THE PLAINS. THE 00Z ECMWF TRENDED  
SLIGHTLY FASTER TOWARD THE 00Z GFS...WHICH IS A STEP AWAY FROM THE  
STRONGER 00Z NAM. THE 00Z UKMET TRENDED MUCH STRONGER WITH  
SHORTWAVE ENERGY CROSSING THE SOUTHWEST U.S./MEXICO BORDER AND  
QUICKER WITH THE PLAINS SHORTWAVE...FASTER THAN MOST OF THE LATEST  
ENSEMBLE MEMBERS. CURRENTLY...A 00Z GFS/ECMWF BLEND APPEARS BEST  
FOR ALL FORECAST HOURS THROUGH 12Z/09 REGARDING THIS SYSTEM.  
 
...DEEP CYCLONE DROPPING FROM THE GULF OF ALASKA TO OFFSHORE OF  
THE PACIFIC NORTHWEST BY WEDNESDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: AVERAGE  
 
THE MODELS ARE OVERALL IN FAIRLY GOOD AGREEMENT WITH THIS SYSTEM  
BUT SOME DIFFERENCES IN PLACEMENT AND STRENGTH OF THE LOW BEGIN TO  
EMERGE BY WEDNESDAY NIGHT. ENSEMBLE SCATTER LOW PLOTS ARE FAIRLY  
WIDE RANGING BY THU MORNING OFF OF THE PACIFIC NORTHWEST...BUT 00Z  
DETERMINISTIC GUIDANCE IS NEAR THE ENSEMBLE MEANS. THE STRENGTH OF  
THE ENSEMBLE MEANS IS 993-995 MB AT 12Z/09 WHICH IS NEAR A BLEND  
OF THE 00Z NAM/GFS/ECMWF/UKMET. THE 00Z CMC IS 984 MB...LIKELY TOO  
DEEP BUT THE NON-00Z CMC MODELS COULD BE TOO WEAK GIVEN THEIR  
SIMILAR DEPTH TO THE ENSEMBLE MEANS AT F084 HOURS. A GENERAL MODEL  
BLEND FOR PLACEMENT AND STRENGTH SHOULD ALLOW FOR A DECENT  
POSITION COMPROMISE WITH A STRENGTH BETWEEN THAT OF THE 00Z CMC  
AND NON-00Z MODELS.  
 
...SOUTHERN END OF DEEP UPPER TROUGH LOCATED OVER THE N-CNTRL U.S.  
BY THU MORNING...   
..COLD FRONT SWEEPING THROUGH THE MS VALLEY WED/THU
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z ECMWF  
CONFIDENCE: AVERAGE  
 
BOTH THE 00Z GFS AND 00Z CMC LIE TOWARD THE DEEPER/FASTER SIDE OF  
THE LATEST ENSEMBLE GUIDANCE WITH SHORTWAVE ENERGY DIVING DOWN THE  
WEST SIDE OF AN ANOMALOUS CLOSED LOW OVER WESTERN HUDSON BY ON  
WED. THE MIDDLE OF THE SPREAD IS BETTER REPRESENTED BY A 12Z  
ECMWF/00Z NAM BLEND...OR NEAR THE 00Z ECMWF WHICH TRENDED A LITTLE  
DEEPER COMPARED TO ITS 12Z RUN. WHILE ENSEMBLE TRENDS HAVE BEEN  
FASTER...THERE HAS BEEN GREATER CONVERGENCE OF ENSEMBLE MEMBERS  
NEAR OR SLIGHTLY WEAKER THAN THE 00Z ECMWF VERSUS THE FASTER 00Z  
CMC/00Z GFS.  
 
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