383  
FXUS10 KWNH 101847  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
146 PM EST FRI NOV 10 2017  
 
VALID NOV 10/1200 UTC THRU NOV 14/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH LATEST MODEL PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
   
..LEAD SHORTWAVE OVER NORTHWEST MT
 
EJECTING EAST ALONG THE  
US-CANADA BORDER THROUGH THE WEEKEND...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-CMC CONSENSUS  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THIS SHORTWAVE IS AN INITIAL WAVE GETTING KICKED OUT OF THE  
BROADER TROUGH NEAR THE PACIFIC NORTHWEST COAST CURRENTLY. THE 12Z  
CMC IS A LITTLE SLOWER THAN THE MODEL CONSENSUS WITH THIS ENERGY  
BY SUNDAY AND STILL SUGGESTS SOME POTENTIAL INTERACTION WITH A  
TRAILING SHORTWAVE WHICH IS THE AFOREMENTIONED TROUGH NEAR THE  
PACIFIC NORTHWEST. THE REMAINING MODELS ARE IN GOOD AGREEMENT IN  
GRADUALLY DAMPENING THIS INITIAL SYSTEM OUT AS IT CLIPS THE UPPER  
GREAT LAKES REGION AND NORTHERN MAINE THROUGH SUNDAY. WILL SUGGEST  
A NON-CMC CONSENSUS AT THIS POINT.  
 
...CLOSED LOW JUST OFFSHORE OF THE PACIFIC NORTHWEST OPENING INTO  
A TROUGH AND MOVING ONSHORE TODAY...   
..BROAD TROUGH REACHING THE NORTHERN PLAINS SATURDAY
 
AND THE  
GREAT LAKES BY SUNDAY...  
...ENERGY REACHING THE MID-ATLANTIC AND NORTHEAST WITH WAVE  
DEVELOPMENT OFFSHORE BY MONDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF 12Z GFS...12Z UKMET AND 12Z ECMWF  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE MODELS SHOW GOOD AGREEMENT WITH THIS SYSTEM AS IT TRAVERSES  
THE WESTERN U.S. AND EJECTS OUT ACROSS THE NORTHERN PLAINS THROUGH  
SATURDAY. HOWEVER...BY SUNDAY AS THE SYSTEM MOVES THROUGH THE  
GREAT LAKES AND OH VALLEY...THE 12Z NAM AND 12Z CMC BEGIN TO  
BECOME MORE AMPLIFIED THAN ANY OTHER SOLUTION. THIS CARRIES OVER  
THROUGH MONDAY AS THE ENERGY REACHES THE MID-ATLANTIC AND  
NORTHEAST. THE STRONGER NAM AND CMC LEAD TO A STRONGER SURFACE  
RESPONSE OFFSHORE SOUTHERN NEW ENGLAND AS CYCLOGENESIS TAKES PLACE  
BY THE END OF THE PERIOD. THE 12Z GFS/12Z UKMET AND 12Z ECMWF ARE  
ALL A BIT WEAKER WITH THIS SYSTEM AND ALSO HAVE RATHER STRONG  
ENSEMBLE SUPPORT WITH A FLATTER WAVE. WILL PREFER A BLEND OF THE  
WEAKER CONSENSUS AT THIS TIME...AND GIVEN THE PROGRESSIVE NATURE  
OF THE MEAN LAYER FLOW...THE SURFACE WAVE SHOULD MOVE OUT TO SEA  
WITH ONLY MODEST IMPACTS TO NEW ENGLAND.  
 
...UPPER TROUGH DROPPING SOUTH OFFSHORE THE PACIFIC NORTHWEST THIS  
WEEKEND BEFORE MOVING INLAND ON MONDAY...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-CMC CONSENSUS  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE GUIDANCE CONTINUES TO ALLOW A DEEP UPPER TROUGH AND ASSOCIATED  
CLOSED LOW TO DROP SOUTH THROUGH THE WEEKEND OFFSHORE THE PACIFIC  
NORTHWEST BEFORE THEN PIVOTING EAST AND INLAND ACROSS THE  
NORTHWEST THROUGH MONDAY. THIS WILL DRIVE LOW PRESSURE ACROSS  
VANCOUVER ISLAND AND A COLD FRONT INLAND ACROSS THE COASTAL RANGES  
OF WA/OR AND INTERIOR SECTIONS OF THE NORTHWEST. THE 12Z CMC IS A  
BIT SLOWER WITH THE HEIGHT FALL EVOLUTION AND TENDS TO FOCUS ITS  
LOW CENTER GENERALLY NORTH AND EAST OF THE MODEL CONSENSUS. THE  
REMAINING MODELS ARE WELL CLUSTERED WITH TIMING AND DEPTH OUTSIDE  
OF SOME MINOR DETAIL DIFFERENCES AND SO WILL SUGGEST A NON-CMC  
CONSENSUS AT THIS TIME.  
 
...POWERFUL OCCLUDING CYCLONE OVER EASTERN CANADA TODAY AND  
SATURDAY WITH ACCOMPANYING COLD FRONT SURGING THROUGH THE  
NORTHEASTERN US...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
MODELS SHOW VERY GOOD AGREEMENT WITH THIS SYSTEM WITH ALL OF THE  
MASS FIELDS...AND THUS WILL CONTINUE TO PREFER A GENERAL MODEL  
BLEND.  
 
WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page