987   
FXUS10 KWNH 301843  
PMDHMD  
  
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 PM EDT WED OCT 30 2019  
  
VALID OCT 30/1200 UTC THRU NOV 03/0000 UTC  
  
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
  
12Z FINAL MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
CENTRAL TO EASTERN U.S. STORM THROUGH FRIDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH THURSDAY EVENING, THEN  
GFS/ECMWF/UKMET  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
  
AN IMPRESSIVE AND DEEP UPPER LEVEL TROUGH OVER THE PLAINS ON  
WEDNESDAY, WITH A WELL-DEFINED SOUTHERN STREAM COMPONENT, WILL  
CONTINUE THE ACTIVE WEATHER PATTERN THROUGH HALLOWEEN FOR THE  
CENTRAL AND EASTERN PART OF THE NATION.  THIS FEATURE SHOULD THEN  
CLOSE OFF AND ACQUIRE NEGATIVE TILT AS IT RAPIDLY LIFTS NORTHEAST  
ACROSS THE LOWER GREAT LAKES AND NORTHEAST THURSDAY NIGHT AND INTO  
FRIDAY MORNING.  MULTIPLE WAVES OF LOW PRESSURE DEVELOPING ALONG  
AN ATTENDANT COLD FRONT WILL INITIALLY EVOLVE OVER PORTIONS OF THE  
TN/OH VALLEYS BY LATE WEDNESDAY, BUT THESE LOWS WILL CONSOLIDATE  
INTO ONE DOMINANT WAVE OF LOW PRESSURE, WHICH WILL DEEPEN OVER THE  
UPPER OHIO VALLEY ON THURSDAY BEFORE LIFTING UP THROUGH THE LOWER  
GREAT LAKES AND NORTHEAST.  A STRONG COLD FRONT TRAILING SOUTH  
FROM THE SURFACE LOW WILL CROSS THE EASTERN U.S. AND REACH THE  
EAST COAST BY LATER THURSDAY NIGHT.  
  
THE MODELS ARE INDICATING GOOD OVERALL SYNOPTIC SCALE AGREEMENT  
THROUGH ABOUT 36 HOURS, AFTER WHICH THE NAM BECOMES STRONGER WITH  
THE UPPER LOW ACROSS THE GREAT LAKES AND NORTHERN NEW ENGLAND.   
THE GFS BECOMES SLIGHTLY MORE AMPLIFIED AT THE 500-700MB LEVEL  
ACROSS THE OHIO VALLEY AND GREAT LAKES.  ALL OF THE MODELS AGREE  
ON THE COLD FRONT TIMING ACROSS THE EAST COAST THURSDAY NIGHT.  NO  
SIGNIFICANT CHANGES FROM THE EARLIER MODEL DISCUSSION SO PREVIOUS  
PREFERENCES REMAIN IN PLACE.  
  
NEXT UPPER TROUGH/FRONT OVER THE PLAINS/MIDWEST BY THIS WEEKEND  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH FRIDAY MORNING, THEN  
ECMWF/GFS/CMC BLEND  
CONFIDENCE: ABOVE AVERAGE  
  
AFTER A BRIEF PERIOD OF UPPER LEVEL RIDGING ACROSS THE  
NORTH-CENTRAL U.S. ON THURSDAY, THE NEXT UPPER LEVEL TROUGH  
SETTLES SOUTHWARD FROM WESTERN CANADA AND ENCOMPASSES MUCH OF THE  
CENTRAL AND EASTERN PLAINS BY FRIDAY.  BROAD CYCLONIC FLOW FROM  
THE DEEP SOUTH TO THE GREAT LAKES WILL BE IN PLACE BY SATURDAY,  
AND AN UPPER LEVEL RIDGE BUILDS ACROSS THE WEST COAST IN RESPONSE.  
 THE NAM IS MORE AMPLIFIED AND SLOWER THAN THE MODEL CONSENSUS AT  
ALL LEVELS, AND THE 12Z UKMET IS SLIGHTLY FASTER THAN THE MODEL  
CONSENSUS, WITH GOOD OVERALL AGREEMENT AMONG THE REMAINING  
GUIDANCE.  
  
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
  
HAMRICK  
  
  
 
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