173  
FXUS10 KWNH 140657  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
256 AM EDT THU MAY 14 2020  
 
VALID MAY 14/0000 UTC THRU MAY 17/1200 UTC  
 
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
...CLOSED LOW OVER ALBERTA TRACKING TO THE UPPER GREAT LAKES  
THU...THEN ACROSS NORTHERN NEW ENGLAND FRI...  
...SURFACE LOW MOVING FROM THE NORTH CENTRAL US TONIGHT INTO  
NORTHERN NEW ENGLAND FRI...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z NAM, 00Z ECMWF, GEFS/ECENS BLEND  
CONFIDENCE: AVERAGE  
 
07Z UPDATE: NO SIGNIFICANT CHANGES NOTED WITH THE REST OF THE  
GUIDANCE. THE 00Z ECMWF TRENDED FAVORABLY FROM ITS PRIOR RUN AND  
IS FAVORED.  
 
---PREVIOUS DISCUSSION---  
SHORTWAVE ENERGY WILL MOVE FROM SOUTHERN ALBERTA AND NORTHERN  
PLAINS TOWARD THE GREAT LAKES OVER THE NEXT 24 HOURS. THROUGH  
ABOUT 15.12Z, THE GUIDANCE SHOWS ABOVE AVERAGE AGREEMENT ALOFT AND  
AT THE SURFACE, BUT BEYOND THAT TIME FRAME, TIMING DIFFERENCES  
BEGIN TO CREEP UP. THE GFS BECOMES A SLOWER OUTLIER ALONG WITH THE  
CMC. THE NAM/ECMWF OFFER A MIDDLE GROUND APPROACH WITH THE UKMET A  
BIT AHEAD OF THE REST OF THE DETERMINISTIC GUIDANCE. LOOKING AT  
THE ENSEMBLES, THE GEFS/ECENS MEANS WOULD ALSO BE A GOOD APPROACH  
AFTER 15.12Z.  
 
....CLOSED MID LEVEL LOW OFF THE PACIFIC NORTHWEST COAST  
THU...MOVING TO THE NORTHERN PLAINS SAT...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
07Z UPDATE: NO CHANGES FROM PREVIOUS PREFERENCE.  
 
---PREVIOUS DISCUSSION----  
MODEL GUIDANCE CONFIDENCE AND AGREEMENT REMAINS ABOVE AVERAGE WITH  
THE EXPECTED EVOLUTION OF A CLOSED UPPER LEVEL LOW OFF THE PACIFIC  
NORTHWEST COAST LATER TODAY THAT THEN TRACKS THROUGH THE NORTHERN  
ROCKIES THROUGH THE END OF THE FORECAST PERIOD. A GENERAL MODEL  
BLEND SUFFICES.  
 
   
..MID LEVEL TROUGH OVER NORTHERN MEXICO THU
 
MOVING INTO CENTRAL  
TX SAT...   
..SURFACE LOW OVER EASTERN NM/WEST TX FRI
 
CROSSING INTO CENTRAL  
TX SAT...  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-00Z CMC BLEND  
CONFIDENCE: AVERAGE  
 
07Z UPDATE: NO CHANGES FROM PREVIOUS DISCUSSION, THE 00Z CMC  
REMAINS THE SOUTHERN OUTLIER BUT THE SPREAD HAS LESSENED SOMEWHAT  
FROM THE 12Z CYCLE.  
 
---PREVIOUS DISCUSSION---  
LONGWAVE TROUGHING OVER NORTHERN MEXICO TODAY IS FORECAST TO TRACK  
EASTWARD OVER NEW MEXICO INTO CENTRAL TEXAS BY SATURDAY. OVERALL,  
MODEL CLUSTERING HAS IMPROVED WITH THE MID LEVEL FEATURE BUT THERE  
REMAINS SOME LATITUDINAL SPREAD IN THE FEATURE, ESPECIALLY AFTER  
60 HOURS. THE ECMWF, WHILE AN EARLIER NORTHERN SOLUTION, HAS  
REMAINED CONSISTENT WITH SOME NORTHWARD ADJUSTMENT/TREND SEEN IN  
THE 00Z GFS AND 00Z NAM. THIS NOW SOLIDLY PUTS THE CMC AS A  
SOUTHERN OUTLIER AND A BIT OUTSIDE THE ENSEMBLE RANGE. FOR THIS  
REASON, THE PREFERRED BLEND REMOVES THE CMC AND GOES WITH A NEAR  
EQUAL WEIGHT OF THE REST AVAILABLE GUIDANCE.  
 
   
..LOW PRESSURE DEVELOPING NEAR THE BAHAMAS FRI NIGHT INTO SAT
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: 00Z GFS/12Z ECMWF/18Z GEFS MEAN/12Z ECMWF MEAN BLEND  
CONFIDENCE: AVERAGE  
 
07Z UPDATE: NO MAJOR CHANGES TO THE MODEL GUIDANCE TRACK OF THE  
LOW PRESSURE OVER THE FORECAST PERIOD. THE CMC REMAINS A WESTERN  
OUTLIER WHILE THE UKMET IS TO THE EAST. THE ECMWF/GFS AND THEIR  
RESPECTIVE ENSEMBLE MEANS REMAINS THE FAVORED BLEND.  
 
---PREVIOUS DISCUSSION---  
THE 00Z GFS DID NOT STRAY TOO FAR FROM ITS EARLIER RUNS AND  
REMAINS A CONSENSUS APPROACH ALONG WITH THE 12Z ECMWF, AS THE AREA  
OF LOW PRESSURE NEAR THE FL COAST GRADUALLY ORGANIZES AS IT MOVES  
NORTH/NORTHEAST. THE 18Z GEFS AND 12Z ECENS MEANS ALSO REMAIN  
USEFUL WITH SIMILAR TRACKS AS THE DETERMINISTIC RUNS. THE 12Z CMC  
AND 12Z UKMET REMAIN OUTLIERS AND DISCOUNTED, WHERE THE CMC IS  
CONSIDERABLY TOO FAR TO THE LEFT/WEST, WHILE THE UKMET IS TO THE  
RIGHT/EAST OF THE CONSENSUS. FORECAST CONFIDENCE REMAINS AT  
AVERAGE TO SLIGHTLY ABOVE AVERAGE.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
TAYLOR  
 

 
 
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