983  
ACUS11 KWNS 041812  
SWOMCD  
SPC MCD 041811  
MNZ000-SDZ000-NDZ000-042215-  
 
MESOSCALE DISCUSSION 1777  
NWS STORM PREDICTION CENTER NORMAN OK  
1211 PM CST MON DEC 04 2017  
 
AREAS AFFECTED...PORTIONS OF EASTERN ND...NORTHEAST SD AND NORTHWEST  
AND WEST-CENTRAL MN  
 
CONCERNING...BLIZZARD  
 
VALID 041811Z - 042215Z  
 
SUMMARY...HEAVY SNOW, WITH RATES OF ONE INCH/HOUR WILL BECOME MORE  
WIDESPREAD THROUGH THIS AFTERNOON. INCREASING SURFACE WINDS WITH  
TIME THIS AFTERNOON WILL RESULT IN SOME AREAS EXPERIENCING BLIZZARD  
CONDITIONS.  
 
DISCUSSION...SURFACE LOW PRESSURE OVER SOUTHEAST MN AT 18Z WILL MOVE  
NORTHEAST AND DEEPEN RAPIDLY THIS AFTERNOON AND TONIGHT AS A STRONG  
UPPER-LEVEL SHORTWAVE TROUGH BECOMES INCREASINGLY NEGATIVELY TILTED  
ACROSS PORTIONS OF THE CENTRAL/NORTHERN PLAINS AND UPPER MIDWEST.  
THE COMBINATION OF LOW-LEVEL COLD ADVECTION AND DYNAMIC COOLING DUE  
TO ASCENT WITHIN THE DEFORMATION ZONE WILL RESULT IN THE TRANSITION  
TO SNOW SPREADING FARTHER EAST ACROSS NORTHWEST MN THROUGH THIS  
AFTERNOON. INCREASING LARGE-SCALE ASCENT SHOULD ALSO DEVELOP  
FARTHER SOUTH THIS AFTERNOON, RESULTING IN THE AREA OF SNOW  
DEVELOPING INTO NORTHEAST SD AND WEST-CENTRAL MN. RAP FORECAST  
SOUNDINGS SUPPORT HEAVY SNOW WITH RATES OF ONE INCH/HOUR FOR A FEW  
HOURS AT ANY LOCATION. AN OCCASIONAL LIGHTNING STRIKE IS ALSO  
POSSIBLE IN THE PRESENCE OF MODEST ELEVATED INSTABILITY, RESULTING  
IN BRIEF LOCALLY HEAVIER SNOWFALL RATES.  
 
AS THE SURFACE LOW DEEPENS THIS AFTERNOON AND EVENING, INCREASING  
SURFACE WINDS WILL RESULT IN BLIZZARD CONDITIONS DEVELOPING ACROSS  
MUCH OF THE DISCUSSION AREA.  
 
..BUNTING.. 12/04/2017  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT
 
 
ATTN...WFO...MPX...FGF...ABR...  
 
LAT...LON 48979703 49019591 48929554 48849536 48379529 47989531  
47539535 46499574 45599633 45229667 45099680 45169718  
45569745 47189750 48979703  
 
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