866  
FXUS10 KWNH 011843  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
141 PM EST SAT FEB 01 2020  
 
VALID FEB 01/1200 UTC THRU FEB 05/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
~~~~~~  
   
..TROUGH EVOLUTION OVER THE EASTERN U.S. THROUGH SUNDAY  
   
..DEEPENING COASTAL LOW TRACKING NORTH OFFSHORE OF NEW ENGLAND  
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THE MODELS ARE IN GOOD AGREEMENT WITH THE DETAILS OF THE  
PROGRESSIVE TROUGH MOVING THROUGH THE EASTERN U.S. THIS WEEKEND.  
SURFACE LOW PRESSURE IS STILL EXPECTED TO DEEPEN AND LIFT  
NORTHEAST WELL AWAY FROM THE EAST COAST THROUGH TONIGHT, BUT THE  
LOW CENTER WILL HAVE A DIRECT IMPACT ON PORTIONS OF SOUTHEAST  
CANADA, AND ESPECIALLY THE MARITIMES ON SUNDAY. A GENERAL MODEL  
BLEND WILL BE PREFERRED.  
 
   
..DEEP LONGWAVE TROUGH EVOLVING OVER THE WESTERN U.S.  
   
..SURFACE WAVE ACTIVITY DEVELOPING OVER THE LOWER/MID MS VALLEY  
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF 12Z NAM/CMC/ECMWF AND 12Z GEFS/00Z ECENS MEANS  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE 12Z GFS AGAIN JUST AS IT IN PREVIOUS RUNS CONTINUES TO BE TOO  
PROGRESSIVE WITH THE EVOLUTION OF THE DEEP LONGWAVE TROUGH  
EVOLUTION OVER THE WESTERN U.S. OVER THE NEXT FEW DAYS. THE GFS IN  
BEING MORE PROGRESSIVE WITH ITS HEIGHT FALLS ALSO RESULTS IN THE  
GFS BEING MORE OUT OF TOLERANCE WITH THE REMAINING GUIDANCE  
CONCERNING THE DEVELOPING SURFACE WAVE ACTIVITY OVER THE  
CENTRAL/SOUTHERN PLAINS AND ESPECIALLY THE LOWER/MID MS VALLEY BY  
MONDAY. THE 12Z UKMET DOES APPEAR TO BE A BIT SLOW WITH THE TROUGH  
PROGRESSION TOWARD THE HIGH PLAINS BY THE END OF THE PERIOD, BUT  
THE REMAINING GUIDANCE LED BY THE 12Z NAM, 12Z CMC AND 12Z ECMWF,  
AND ALSO THE LATEST GEFS/ECENS MEANS SHOW GENERALLY GOOD AGREEMENT  
WITH THE TROUGH TIMING/DEPTH AND SURFACE WAVE ACTIVITY. A BLEND OF  
THE NON-GFS/UKMET WILL ACCORDINGLY BE PREFERRED.  
 
   
..NORTHERN STREAM TROUGH CLIPPING THE NORTHERN PLAINS TUESDAY  
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-UKMET BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THE GUIDANCE SHOWS A PROGRESSIVE NORTHERN STREAM TROUGH CLIPPING  
THE NORTHERN PLAINS BY TUESDAY. THE 12Z UKMET IS ON THE FAST SIDE  
OF THE GUIDANCE WITH THIS SYSTEM WITH THE REMAINING MODELS RATHER  
WELL CLUSTERED. SO, A NON-UKMET BLEND WILL BE PREFERRED FOR NOW.  
 
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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