756  
FXUS10 KWNH 141846  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
145 PM EST TUE JAN 14 2020  
 
VALID JAN 14/1200 UTC THRU JAN 18/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..SHORTWAVE CROSSING THE GREAT LAKES/NORTHEAST THROUGH WED
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
THE LOW-AMPLITUDE SHORTWAVE IMPULSE CURRENTLY MOVING INTO THE  
GREAT LAKES REGION WILL CROSS THE NORTHEAST ON WEDNESDAY. THE  
GUIDANCE IS IN VERY GOOD AGREEMENT WITH THIS SYSTEM, SO A GENERAL  
MODEL BLEND WILL BE PREFERRED.  
 
   
..SHORTWAVE CURRENTLY OVER THE NORTHWEST
 
   
..CROSSING THE UPPER MIDWEST/NORTHEAST THROUGH WED/THURS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 12Z GFS/CMC/ECMWF  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE SHORTWAVE TROUGH MOVING ACROSS THE NORTHWEST AROUND THE BASE  
OF THE DEEP UPPER LOW OVER SOUTHWEST CANADA WILL EJECT QUICKLY  
EAST ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST THROUGH  
WEDNESDAY, AND THEN AMPLIFY INTO THE NORTHEAST ON THURSDAY.  
SURFACE LOW PRESSURE ASSOCIATED WITH THIS SYSTEM WILL CROSS THE  
MIDWEST AND ADVANCE THROUGH NEW YORK AND NEW ENGLAND EARLY  
THURSDAY BEFORE DEEPENING OVER THE GULF OF MAINE BY MIDDAY  
THURSDAY. THE GUIDANCE IS IN GOOD AGREEMENT UNTIL IT ARRIVES  
ACROSS THE NORTHEAST WHERE THE 12Z NAM BEGINS TO EDGE A TAD  
STRONGER THAN THE GLOBAL MODELS WITH THE UPPER TROUGH, AND ALSO  
TENDS TO TUCK THE SURFACE LOW IN A LITTLE CLOSER TO EASTERN MAINE.  
THERE IS A LITTLE BIT OF LATITUDINAL SPREAD SEEN WITH THE GLOBAL  
MODELS AS THE 12Z NON-NCEP GUIDANCE IS A TAD SOUTH OF THE NAM AND  
GFS SOLUTIONS. THE 12Z UKMET IS OVERALL THE FARTHEST SOUTH AS THE  
LOW EJECTS THROUGH THE GULF OF MAINE. ACCOUNTING FOR THE NAM AND  
UKMET SOLUTIONS, THE PREFERENCE WILL BE TOWARD A BLEND OF THE GFS,  
CMC AND ECMWF AT THIS TIME WHICH IS REASONABLY WELL SUPPORTED BY  
THE LATEST GEFS/ECENS MEANS.  
 
   
..DEEP UPPER TROUGH CROSSING INTO THE WEST BY THURS
 
   
..EJECTING OUT ACROSS THE PLAINS/MIDWEST LATE FRI
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 12Z ECMWF/GEFS AND 00Z ECENS  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE GUIDANCE BRINGS A STRONG DEEP LAYER TROUGH INTO THE WEST BY  
THURSDAY WITH THE HEIGHT FALLS AND AN AREA OF LEESIDE CYCLOGENESIS  
THEN EJECTING OUT ACROSS THE PLAINS AND MIDWEST ON FRIDAY. THE 12Z  
GFS IS ON THE FASTER SIDE OF THE GUIDANCE BY LATE FRIDAY WITH THE  
12Z NAM THE SLOWEST. THE NAM ALSO IS APPEARING TO BE A BIT TOO  
DEEP WITH THE NORTHERN PORTION OF THE TROUGH AS IT EJECTS ACROSS  
THE NORTHERN PLAINS. GENERALLY, THE 12Z NON-NCEP MODELS SPLIT THE  
DIFFERENCE. THE 12Z ECMWF APPEARS TO BEST APPROXIMATE THE MODEL  
CONSENSUS, AND HAS GOOD SUPPORT FROM THE LATEST GEFS/ECENS SUITES.  
A BLEND OF THE ECMWF AND ENSEMBLE MEANS WILL BE PREFERRED.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 

 
 
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