790  
FXUS10 KWNH 071849  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
148 PM EST TUE NOV 07 2017  
 
VALID NOV 07/1200 UTC THRU NOV 11/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..COLD FRONT PUSHING INTO THE SOUTHEAST
 
   
..EXITING TN VALLEY LOW WITH REDEVELOPMENT OFF THE EAST COAST
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 12Z GFS/UKMET/ECMWF  
CONFIDENCE: ABOVE AVERAGE  
 
THE MODELS TAKE A WAVE OF LOW PRESSURE AND AN ASSOCIATED SURFACE  
WAVE OUT OF THE TN VALLEY TODAY AND OFFSHORE THE MID-ATLANTIC  
STATES BY TONIGHT. LOW PRESSURE IS EXPECTED TO REDEVELOP OFF THE  
MID-ATLANTIC COAST OVERNIGHT AND WILL LIFT NORTHEAST AND OFFSHORE  
NEW ENGLAND ON WEDNESDAY. THE 12Z NAM/CMC SOLUTIONS TRACK THEIR  
LOW CENTERS A TAD LEFT OF THE OTHERWISE WELL CLUSTERED 12Z  
GFS/UKMET/ECMWF SOLUTIONS. THE LATEST GEFS MEAN AND ECENS MEAN  
FAVOR THE GFS/UKMET/ECMWF CLUSTER...AND SO A BLEND OF THOSE  
SOLUTIONS WILL BE PREFERRED.  
 
   
..POSITIVELY TILTED TROUGH EXITING THE WEST TODAY
 
   
..ENERGY CROSSING THE PLAINS ON WEDNESDAY
 
   
..REACHING THE SOUTHEAST BY THURSDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 12Z UKMET  
CONFIDENCE: AVERAGE  
 
THE MODELS TAKE A POSITIVELY-TILTED TROUGH EAST OUT OF THE  
INTERMOUNTAIN WEST AND ACROSS THE PLAINS THROUGH WEDNESDAY. THIS  
ENERGY WILL REACH THE SOUTHEAST BY THURSDAY BEFORE THEN EXITING  
OFF THE SOUTHEAST COAST. THE 12Z GFS AND 12Z CMC ARE BOTH A BIT  
MORE PROGRESSIVE WITH THE ENERGY AS IT TRAVERSES THE SOUTHEAST  
COMPARED TO THE MODEL CONSENSUS. MEANWHILE...THE 12Z NAM AND 12Z  
ECMWF ARE BOTH A TAD MORE ENERGETIC/STRONGER WITH THE SYSTEM AS IT  
CROSSES THE GULF COAST STATES. THE 12Z UKMET GENERALLY APPEARS  
CLOSEST TO THE MODEL CONSENSUS AT THIS POINT...AND SO WILL LEAN  
TOWARD THE UKMET AT THIS TIME.  
 
...DEEP CYCLONE DROPPING FROM THE GULF OF ALASKA TO OFFSHORE OF  
THE PACIFIC NORTHWEST...   
..OPENING INTO A TROUGH OVER THE NORTHWEST BY FRIDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-CMC CONSENSUS  
CONFIDENCE: AVERAGE  
 
A DEEP UPPER LOW OVER THE GULF OF AK WILL DROP SOUTH-SOUTHEAST AND  
THEN GRADUALLY EAST TOWARD THE PACIFIC NORTHWEST BY THURSDAY  
BEFORE THEN WEAKENING INTO A PROGRESSIVE TROUGH AXIS AND MOVING  
INLAND ACROSS THE NORTHWEST ON FRIDAY. THE MODELS ARE IN GOOD  
AGREEMENT THROUGH ABOUT 60 HOURS...BUT THEN THE 12Z CMC BECOMES A  
MORE PROGRESSIVE OUTLIER AS THE ENERGY BEGINS TO SHEAR OUT ACROSS  
THE NORTHERN PLAINS. WILL PREFER A NON-CMC CONSENSUS AT THIS TIME.  
 
   
..AMPLIFYING NORTHERN STREAM TROUGH/CLOSED LOW NEAR GREAT LAKES
 
   
..COLD FRONT CROSSING THE NORTHERN TIER STATES WED-FRI
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-UKMET CONSENSUS  
CONFIDENCE: AVERAGE  
 
OVERALL...THE MODELS ARE IN GOOD AGREEMENT WITH THE THE DETAILS OF  
A VIGOROUS NORTHERN STREAM TROUGH THAT AMPLIFIES INTO A CLOSED LOW  
NORTH OF THE GREAT LAKES REGION ACROSS ONTARIO AND SOUTHERN QUEBEC  
BY THE END OF THE WEEK. THE 12Z UKMET AMPLIFIES ITS ENERGY A BIT  
NORTH OF THE OTHERWISE WELL-CLUSTERED GUIDANCE...WHICH ALSO ALLOWS  
DEEPENING SURFACE LOW PRESSURE CROSSING THE GREAT LAKES REGION TO  
LIFT FARTHER NORTH COMPARED TO THE MODEL CONSENSUS BY THE END OF  
THE PERIOD. WILL PREFER A NON-UKMET CONSENSUS AS A RESULT.  
 
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ORRISON  
 

 
 
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