279  
FXUS10 KWNH 050416  
PMDHMD  
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1215 AM EDT SAT OCT 05 2019  
 
VALID OCT 05/0000 UTC THRU OCT 08/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
W/LOWER WEIGHTING TO 00Z NAM IN TN VALLEY ON D3  
CONFIDENCE: ABOVE AVERAGE  
 
THE LARGE SCALE FLOW PATTERN ACROSS THE CONUS OVER THE NEXT FEW  
DAYS WILL FEATURE MULTIPLE PROGRESSIVE NORTHERN STREAM TROUGHS AND  
A TROPICAL WAVE SUPPORTING SURFACE DEVELOPMENT NORTHEAST OF THE  
BAHAMAS AND PARALLELING THE SOUTHEAST COAST THROUGH TUES. THE  
SHORTWAVE LIFTING OUT OF THE WY ROCKIES CURRENTLY WILL PROGRESS  
THROUGH MN INTO ONTARIO BY SUNDAY WITH A DRAPED BUT PROGRESSIVE  
FRONT PROGRESSING THROUGH THE MIDWEST AND OHIO VALLEYS WITH THE  
TAIL END FLATTENED ACROSS THE OK S PLAINS INTO CENTRAL MS/W TN  
VALLEY BY THE END OF THE FORECAST PERIOD. GUIDANCE CONTINUES TO  
BE QUITE AGREEABLE EVEN THROUGH THE DAY 3 PERIOD, THOUGH TYPICAL  
BIASES START TO MANIFEST BY DAY 3. THE 00Z GFS IS FASTER AND  
GENERALLY WEAKER WITH THE TRAILING SHORTWAVE ENERGY/FRONTAL ZONE  
IN THE MS/TN VALLEY RELATIVE TO THE OTHER GUIDANCE, WHILE THE 00Z  
NAM CONTINUES TO BE A BIT STRONGER ALLOWING FOR A BIT OF WAVE  
DEVELOPMENT IN THE TN VALLEY BY LATE MON/EARLY TUES. STILL, BOTH  
00Z GFS/NAM ARE TRENDING TOWARD A COMMON SOLUTION WITH THE  
UKMET/CMC/ECWMF SOLUTIONS. THE UKMET IS LIKE THE GFS, SLIGHTLY  
FASTER AND WEAKER IN TRAILING BOUNDARY, WHILE THE ECMWF/CMC ARE A  
BIT SLOWER AND MORE AMPLIFIED WITH A WEAK WAVE IN TN (THOUGH NOT  
AS MUCH AS THE NAM). ALL IN ALL, THIS IS GREAT AGREEMENT AND A  
GENERAL MODEL BLEND CAN BE EMPLOYED WITH ABOVE AVERAGE CONFIDENCE,  
THOUGH PERHAPS FADING THE WEIGHTING OF THE NAM AFTER 72HRS IN TN  
VALLEY.  
 
THE TROPICAL WAVE PROGRESSING ACROSS THE SOUTHEAST ATLANTIC WILL  
APPROACH THE BAHAMAS AND START TO TURN NORTH. THIS INCREASED  
CONVERGENCE AND UPPER LEVEL BAROCLINIC OUTFLOW/SUPPORT WILL HELP  
TO DEEPEN A SURFACE WAVE OFF THE COAST. THE SLOWER/STRONGER  
SOUTHERN SHORTWAVE SOLUTIONS OF THE NAM/ECMWF/CMC SUPPORT A  
STRONGER SURFACE WAVE WHILE THE GFS IS A BIT WEAKER. THE UKMET IS  
SLOW OVERALL WITH THE TROPICAL WAVE AND LAGS FURTHER. HOWEVER,  
OVERALL, THERE IS SOLID GUIDANCE TO SUPPORT A GENERAL MODEL BLEND  
PERHAPS CLOSER TO THE GEFS/ECENS MEAN SOLUTIONS GIVEN THE MODERATE  
SPREAD/UNCERTAINTY RELATED TO MORE RANDOM CONVECTIVE DEVELOPMENT  
DEEPENING THE WAVE MORE OR LESS DEPENDENT ON THE MODEL AND THE  
RUN. AS SUCH A GENERAL MODEL BLEND IS SUPPORTED BUT AT AVERAGE TO  
SLIGHTLY ABOVE AVERAGE CONFIDENCE FOR THIS FEATURE.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
GALLINA  
 

 
 
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