051  
FXUS10 KWNH 080632  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
131 AM EST WED JAN 08 2020  
 
VALID JAN 08/0000 UTC THRU JAN 11/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..NORTHERN STREAM TROUGH CROSSING THE NORTHEAST ON WED
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THE MODELS ADVANCE A NORTHERN STREAM UPPER TROUGH AND ATTENDANT  
COLD FRONT ACROSS THE NORTHEAST ON WEDNESDAY. VERY GOOD MODEL  
AGREEMENT CONTINUES, AND SO A GENERAL MODEL BLEND WILL AGAIN BE  
PREFERRED.  
 
   
..INITIAL SHORTWAVE CROSSING THE PACIFIC NORTHWEST
 
   
..ENERGY ADVANCING EAST ACROSS THE NORTHERN PLAINS/MIDWEST
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND...THROUGH 36 HOURS  
NON-NAM BLEND...AFTER 36 HOURS  
CONFIDENCE: ABOVE AVERAGE  
 
THE MODELS ARE IN GOOD AGREEMENT WITH THE CURRENT SHORTWAVE THAT  
IS MOVING ACROSS THE PACIFIC NORTHWEST. THIS ENERGY RAPIDLY EJECTS  
OUT ACROSS THE PLAINS AND UPPER MIDWEST GOING THROUGH THURSDAY.  
THE 00Z NAM THOUGH EVENTUALLY APPEARS TO BE A TAD TOO FAR NORTH  
WITH ITS DOWNSTREAM LOW TRACK NEAR THE UPPER MIDWEST, UPPER GREAT  
LAKES AND PORTIONS OF ONTARIO. A GENERAL MODEL BLEND WILL BE  
PREFERRED THROUGH ABOUT 36 HOURS, BUT THEREAFTER, A NON-NAM BLEND  
WILL BE RECOMMENDED.  
 
   
..SHORTWAVE AMPLIFYING ACROSS THE FOUR CORNERS/HIGH PLAINS
 
   
..DEEPENING SURFACE LOW OVER THE LOWER MS VALLEY FRI/SAT
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 00Z UKMET/CMC/ECMWF  
CONFIDENCE: AVERAGE  
 
A SECOND SHORTWAVE TROUGH CROSSING THE PACIFIC NORTHWEST BY EARLY  
THURSDAY IS EXPECTED TO DIVE SOUTHEAST AND BECOME DETACHED FROM  
THE WESTERLIES AS IT CROSSES THE FOUR CORNERS REGION. THIS ENERGY  
THEN WILL AMPLIFY SHARPLY OUT ACROSS THE SOUTHERN PLAINS ON  
FRIDAY, BEFORE THEN BEGINNING TO LIFT NORTHEASTWARD THROUGH THE  
LOWER/MID MS VALLEY BY SATURDAY. A VERY STRONG FRONTAL ZONE WILL  
BE SETTING UP ACROSS THIS REGION FOR THE WEEKEND, AND LOW PRESSURE  
WILL BE DEVELOPING ALONG IT AND RIDING NORTHEASTWARD. THE 00Z  
NAM/GFS SOLUTIONS ARE MORE PROGRESSIVE THAN THE 00Z NON-NCEP  
MODELS AS THE ENERGY EJECTS ACROSS THE SOUTHERN PLAINS AND  
LOWER/MID MS VALLEY. THE NAM ALSO ENDS UP BEING A BIT STRONGER  
WITH ITS HEIGHT FALLS COMPARED TO THE GLOBAL MODEL SUITE. THE  
LATEST GEFS AND ECENS SUITES SUPPORT A SOMEWHAT SLOWER TROUGH  
EVOLUTION LIKE THE COLLECTIVE NON-NCEP CAMP, AND AS A RESULT, THE  
MORE PROGRESSIVE NAM/GFS SOLUTIONS WILL NOT BE PREFERRED AT THIS  
TIME. ANOTHER CONSIDERATION IS THE ANOMALOUSLY STRONG DOWNSTREAM  
RIDGE DEVELOPING OVER THE SOUTHWEST ATLANTIC WHICH SHOULD TEND TO  
FOSTER AT LEAST A LESS PROGRESSIVE SOUTHERN STREAM FLOW PATTERN.  
SO, FOR NOW, A BLEND OF THE 00Z UKMET/CMC/ECMWF SOLUTIONS WILL BE  
PREFERRED.  
 
   
..NEXT UPPER TROUGH OVER THE NORTHWEST BY SAT
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-NAM BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
YET ANOTHER SHORTWAVE TROUGH WILL CROSS INTO THE NORTHWEST BY  
SATURDAY. THE 00Z NAM APPEARS TO BE A TAD TOO DEEP AND SLOW WITH  
THIS SYSTEM. THE GLOBAL MODELS ARE RATHER WELL CLUSTERED THOUGH,  
AND THUS A NON-NAM BLEND WILL BE PREFERRED WITH THIS SYSTEM.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 

 
 
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