470  
FXUS10 KWNH 010638  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
235 AM EDT WED JUL 01 2020  
 
VALID JUL 01/0000 UTC THRU JUL 04/1200 UTC  
 
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
CLOSED LOW/TROUGH EXITING NEW ENGLAND BY THURSDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
MODEL GUIDANCE IS IN EXCELLENT AGREEMENT GRADUALLY TAKING THE  
UPPER LOW AND ASSOCIATED TROUGH AXIS OVER NEW ENGLAND GRADUALLY  
OFF TO THE EAST-SOUTHEAST OVER THE NEXT COUPLE OF DAYS AND  
ULTIMATELY OFFSHORE THE EAST COAST. A GENERAL MODEL BLEND WILL BE  
PREFERRED.  
 
DEEP UPPER TROUGH/CLOSED LOW ACROSS THE INTERMOUNTAIN WEST  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 00Z UKMET/ECMWF AND 12Z ECENS MEAN  
CONFIDENCE: AVERAGE  
 
THE UPPER LOW/TROUGH IMPACTING THE NORTHERN INTERMOUNTAIN REGION  
WILL ADVANCE NORTH INTO SOUTHWEST CANADA ON WEDNESDAY AS ANOTHER  
SHORTWAVE TROUGH DROPS SOUTHWARD OVER THE PACIFIC NORTHWEST. THE  
PHASING OF THIS ENERGY WILL KEEP THE CLOSED LOW IN PLACE OVER  
SOUTHWEST CANADA MUCH OF THE PERIOD. HOWEVER, ANOTHER COMPACT  
CLOSED LOW AND ASSOCIATED TROUGH IS FORECAST TO DROP SOUTH DOWN  
THE COAST OF BRITISH COLUMBIA AND INTO THE PACIFIC NORTHWEST GOING  
THROUGH THURSDAY. THE MODELS GENERALLY SUPPORT TWO CLOSED LOWS  
THEN BY FRIDAY WITH ONE NEAR THE PACIFIC NORTHWEST AND ONE FARTHER  
NORTH OVER PARTS OF ALBERTA. THE 00Z NAM BY FRIDAY TENDS TO BE A  
BIT STRONGER WITH THE BROADER HEIGHT FALL EVOLUTION. THE 00Z CMC  
IS STILL JUST SLIGHTLY OUT OF PHASE COMPARED TO THE MODEL  
CONSENSUS, BUT IT HAS TRENDED TOWARD THE BETTER MODEL CLUSTERING  
OF THE 00Z UKMET AND 00Z ECMWF. THE 00Z GFS NOW AT THIS POINT IS A  
BIT OUT OF PHASE WITH THE 00Z GEFS MEAN AND SUGGESTS STRONGER  
HEIGHT FALLS SHIFTING INTO THE PACIFIC NORTHWEST BY THE END OF  
THER PERIOD COMPARED TO THE MODEL CONSENSUS. THE 00Z GEFS AND  
ESPECIALLY THE 12Z ECENS MEAN FAVOR THE UKMET/ECMWF CAMP. A BLEND  
OF THE UKMET/ECMWF AND LATEST ECENS MEAN WILL BE PREFERRED AT THIS  
TIME.  
 
MCV CROSSING THE MIDWEST THROUGH WEDNESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
A CONVECTIVELY ENHANCED MCV SITUATED ALONG THE IA/IL BORDER, STUCK  
IN BETWEEN A DEEP LAYER RIDGE TO ITS SOUTH AND TO ITS NORTH IS  
FORECAST TO GRADUALLY DAMPEN AND SHEAR OUT OVER THE NEXT COUPLE OF  
DAYS WITH SOME OF THE REMNANT ENERGY DIGGING SOUTHEASTWARD AS THE  
RIDGE OVER THE GULF COAST STATES BREAKS DOWN AND ALLOWS A BROADER  
TROUGH TO ENVELOPE MUCH OF THE DEEP SOUTH AND INTERIOR OF THE  
SOUTHEAST. THE LATEST GUIDANCE GENERALLY AGREES WITH THIS  
SCENARIO, SO A GENERAL MODEL BLEND WILL AGAIN BE PREFERRED WITH  
THIS ENERGY.  
 
MID-LEVEL CLOSED LOW OVER THE GULF COAST BY FRIDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-UKMET BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
MID-LEVEL TROUGHING AND A DEVELOPING CLOSED LOW OVER THE GULF  
COAST STATES IS EXPECTED BY THE END OF THE WEEK, WITH WEAK  
SHORTWAVE ENERGY DROPPING DOWN FROM THE MID-SOUTH. THERE IS DECENT  
AGREEMENT WITH THE LARGER SCALE MASS FIELD EVOLUTION AMONG THE  
MODELS, BUT THE 00Z UKMET BY THE END OF THE PERIOD IS NOTABLY  
WEAKER WITH ITS TROUGHING/CLOSED LOW. THE 00Z GFS ALSO MAY BE A  
TAD ON THE STRONG SIDE, BUT THERE IS SOME ENSEMBLE SUPPORT FOR  
THIS FROM THE LATEST GEFS MEAN, SO FOR NOW A NON-UKMET BLEND WILL  
BE PREFERRED.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 
 
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