086  
FXUS10 KWNH 280643  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
243 AM EDT MON OCT 28 2019  
 
VALID OCT 28/0000 UTC THRU OCT 31/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..DEPARTING MID-LEVEL TROUGH/SURFACE LOW NEAR NEW ENGLAND
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THE LATEST MODEL GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE  
EXITING AND WEAKENING MID-LEVEL TROUGH AND ASSOCIATED SURFACE LOW  
NEAR NEW ENGLAND. A GENERAL MODEL BLEND WILL BE PREFERRED.  
 
   
..MID-LEVEL TROUGH EJECTING INTO THE CENTRAL PLAINS ON MONDAY
 
   
..SURFACE COLD FRONT OVER THE LOWER/MID MS VALLEY BY TUESDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
ALTHOUGH THERE REMAIN SOME MINOR TIMING DIFFERENCES WITH A  
SHORTWAVE REACHING THE CENTRAL PLAINS FROM THE GREAT BASIN ON  
MONDAY, THERE IS ENOUGH AGREEMENT TO SUPPORT A GENERAL MODEL BLEND.  
 
   
..SHORTWAVE/CLIPPER LOW OVER MT/ND BY MONDAY EVENING
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
NO SIGNIFICANT DIFFERENCES EXIST WITH THIS SYSTEM AND RUN TO RUN  
CONTINUITY HAS BEEN GOOD SO ABOVE AVERAGE CONFIDENCE EXISTS FOR A  
GENERAL MODEL BLEND.  
 
   
..POWERFUL CLOSED LOW OVER THE INTERMOUNTAIN WEST BY TUESDAY
 
   
..ENERGY ADVANCING EAST ACROSS THE PLAINS WEDNESDAY
 
   
..COLD FRONT/SURFACE WAVE NEAR OH/TN VALLEYS BY THURSDAY
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 00Z ECMWF AND 12Z ECENS MEAN  
CONFIDENCE: AVERAGE...BECOMING BELOW AVERAGE BY MIDWEEK  
 
A STRONG DEEP LAYER RIDGE OVER THE GULF OF AK WILL SHIFT TOWARD  
NORTHWEST CANADA ON MONDAY WHICH WILL ALLOW SHORTWAVE ENERGY TO  
DIG VIGOROUSLY SOUTHWARD ACROSS SOUTHWEST CANADA AND INTO  
INTERMOUNTAIN WEST, LEADING TO THE DEVELOPMENT OF A DEEP LONGWAVE  
TROUGH OVER THE INTERMOUNTAIN WEST AND HIGH PLAINS BY TUESDAY. AS  
ADDITIONAL ENERGY DIGS INTO THE BACKSIDE OF THE TROUGH ON  
WEDNESDAY, THERE SHOULD BE A STRONG CLOSED LOW EVOLUTION THAT  
SETTLES DOWN TOWARD THE FOUR CORNERS REGION. AS NORTHERN STREAM  
SHORTWAVE ENERGY BEGINS TO BREAK DOWN THE LARGE SCALE RIDGING OVER  
WESTERN CANADA BY THE MIDDLE OF THE WEEK, THE STRONG CLOSED  
LOW/TROUGH WILL BEGIN TO ATTAIN GREATER PROGRESSION OFF TO THE  
EAST WITH THE GUIDANCE SUPPORTING THE CLOSED LOW ADVANCING EAST  
ACROSS THE CENTRAL PLAINS AND REACHING THE MIDDLE MS VALLEY BY  
THURSDAY. THE 00Z NAM IS STILL EXHIBITING SOME TENDENCIES TO BE A  
TAD STRONGER THAN ALL OF THE GLOBAL MODELS WITH THE CLOSED LOW  
EVOLUTION, AND BY THE END OF THE PERIOD, THE NAM BECOMES A SLOW  
OUTLIER. THE 00Z GFS AGAIN IS THE MOST PROGRESSIVE OF ALL OF THE  
DETERMINISTIC MODELS, AND FASTER THAN THE 00Z GEFS MEAN. THE 00Z  
NON-NCEP MODEL SUITE PER THE UKMET, CMC AND ECMWF ARE ALL SLOWER  
THAN THE GFS, BUT NOT AS SLOW AS THE NAM. THE 12Z ECENS MEAN  
SUPPORTS THE NON-NCEP GUIDANCE. THE PREFERENCE AT THIS POINT AT  
THE SURFACE WITH THE COLD FRONT, SURFACE LOW DEVELOPMENT LATE IN  
THE PERIOD TOWARD THE OH/TN VALLEY, AND THE BROADER UPPER  
TROUGH/CLOSED LOW EVOLUTION WILL BE TOWARD A BLEND OF THE ECMWF  
AND ECENS MEAN. CONFIDENCE BECOMES DEGRADED THOUGH BY THE END OF  
THE PERIOD GIVEN THE OVERALL DETERMINISTIC MODEL SPREAD.  
 
   
..POTENTIAL DISTURBANCE IN THE GULF OF MEXICO EARLY NEXT WEEK
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THERE IS CURRENTLY AN AREA OF DISTURBED WEATHER JUST EAST OF THE  
YUCATAN PENINSULA WHICH SOME OF THE MODELS TRACK AROUND THE  
WESTERN SIDE OF THE SUBTROPICAL ATLANTIC RIDGE AND INTO THE GULF  
OF MEXICO OVER THE NEXT 1 TO 2 DAYS. COLLECTIVELY, THE GUIDANCE  
FAVORS LITTLE TO NO DEVELOPMENT OF THIS SYSTEM, BUT THE MODEST  
ENERGY WILL GRADUALLY BECOME ABSORBED BY THE STRONG COLD FRONT  
REACHING THE WESTERN GULF COAST REGION AND LOWER MS VALLEY BY THE  
MIDDLE OF THE WEEK. A GENERAL MODEL BLEND WILL BE PREFERRED.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 

 
 
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