976  
FXUS63 KFSD 140501  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
1101 PM CST WED DEC 13 2017  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 259 PM CST WED DEC 13 2017  
 
STRONG WINDS FROM EARLY WEDNESDAY CONTINUE TO SLOWLY SUBSIDE THIS  
AFTERNOON, AND WILL GRADUALLY TRIM BACK WIND ADVISORY THROUGH THE  
AFTERNOON. FOR THE MOST PART, THE CWA HAS STAYED DRY THROUGH THE  
AFTERNOON. MAY CONTINUE TO SEE A BIT OF LIGHT FLURRIES OR PERHAPS  
VERY LIGHT DRIZZLE OR FREEZING DRIZZLE IN THE BUFFALO RIDGE AREAS  
INTO THE VERY EARLY EVENING HOURS. TRAFFIC CAMERAS ARE NOT SHOWING  
ANY IMPACT IN THE CWA, BUT ARE PICKING UP A BIT OF LOWER CEILINGS  
AND PRECIPITATION INTO NERN SOUTH DAKOTA. HOWEVER IMPACTS ARE  
ANTICIPATED TO BE MINIMAL IF ANY AS TEMPERATURES HOLD NEAR OR ABOVE  
FREEZING.  
 
THE PRIMARY FORECAST CONCERNS OVER THE UPCOMING 24 HOURS ARE  
FOCUSED ON LIGHT SNOW CHANCES ARRIVING LATE TONIGHT AND CONTINUING  
THROUGH THURSDAY. YET ANOTHER SHORTWAVE MOVING THROUGH NORTHERN  
ALBERTA THIS AFTERNOON WILL TRACK NEARLY DUE SOUTH ON THURSDAY  
ACROSS THE WESTERN DAKOTAS. LIFT IS NOT OVERLY IMPRESSIVE WITH  
THIS WAVE, BUT SHOULD BE SUFFICIENT TO PRODUCE AN AREA OF LIGHT  
SNOW. SNOW SHOULD BEGIN IN AREAS ALONG THE MISSOURI RIVER VALLEY  
IN CENTRAL SOUTH DAKOTA NEAR OR AFTER DAYBREAK, WITH A SECONDARY  
AREA OF LIGHT PRECIPITATION SPREADING EASTWARD INTO MN/IA BY MID-  
DAY AND THE AFTERNOON. ACCUMULATIONS SHOULD STAY ON THE LIGHT END  
OF GUIDANCE GIVEN WARMING TEMPERATURES. COULD SEE UPWARDS OF AN  
INCH OF SNOW IN AREAS WEST OF A LINE FROM HURON TO MITCHELL AND  
LAKE ANDES. FURTHER EAST, ONLY A DUSTING TO A COUPLE TENTHS OF  
SNOW ARE ANTICIPATED.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 259 PM CST WED DEC 13 2017  
 
A FAIRLY HIGH DEGREE OF CLOUD COVER, COMBINED WITH WESTERLY WINDS  
WILL HOLD TEMPERATURES IN THE 20S FOR THURSDAY NIGHT.  
 
SHORTWAVE RIDGING MOVES OVERHEAD FOR FRIDAY, PRODUCING A BREEZY  
SOUTHWESTERLY SURFACE WIND. SHOULD SEE TEMPERATURES TRY TO CLIMB  
INTO THE LOWER 40S IN THE AFTERNOON.  
 
A LARGER UPPER TROUGH BEGINS TO MOVE TOWARDS THE NORTHERN PLAINS  
LATE FRIDAY INTO THE UPCOMING WEEKEND. THERE CONTINUES TO BE A FEW  
MODEL DIFFERENCES, BUT THE OVERALL CONSENSUS KEEPS THE AREA DRY WITH  
ABOVE NORMAL TEMPERATURES FRIDAY NIGHT AND SATURDAY WITH A WEAK WARM  
FRONT FOCUSING LIGHT SNOW WELL NORTHEAST OF THE CWA.  
 
A SPLIT IN THE UPPER FLOW PUSHES A WAVE OF ENERGY INTO THE FOUR  
CORNERS REGION, WITH A WEAKER TROUGH PASSING THROUGH THE NORTHERN  
STREAM ALONG THE CANADIAN BORDER LATE ON SATURDAY. THE END RESULT  
WILL BE A TREND TOWARDS DRIER CONDITIONS ON SUNDAY AS ONLY WEAK MID-  
LEVEL FRONTOGENESIS PASSES SOUTHEAST ACROSS THE TRI-STATE REGION.  
 
LITTLE TO NO CHANGE IN THE FORECAST FOR NEXT WEEK AS THE AREA  
REMAINS STUCK IN SLIGHT NORTHWESTERLY FLOW ALOFT AND ON THE EDGE OF  
A SOMEWHAT SUPPRESSED RIDGE OVER THE WESTERN CONUS. THE END RESULT  
WILL BE A CONTINUATION OF ABOVE NORMAL TEMPERATURES AND DRY  
CONDITIONS THROUGH AT LEAST WEDNESDAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)  
ISSUED AT 1100 PM CST WED DEC 13 2017  
 
INTERMITTENT FLURRIES ARE POSSIBLE ALONG THE I-29 CORRIDOR THROUGH  
THE OVERNIGHT HOURS, BUT VERY LITTLE IF ANY ACCUMULATION IS  
EXPECTED. TOMORROW MORNING, A SYSTEM WILL MOVE SOUTH, BRINGING A  
ROUND OF LIGHT SNOW. THE LARGEST ACCUMULATIONS OF AROUND AN INCH  
ARE EXPECTED WEST OF I-29. CEILINGS AND VISIBILITIES WILL LOWER  
DURING PERIODS OF SNOW, WITH MVFR CONDITIONS LIKELY AND BRIEF IFR  
CONDITIONS POSSIBLE. WINDS WILL BE LIGHT, GUSTING IN THE 15 TO 20  
KT RANGE, WITH SNOW ENDING AROUND 15/0200Z FOR MOST LOCATIONS.  
 

 
   
FSD WATCHES/WARNINGS/ADVISORIES
 
 
SD...NONE.  
MN...NONE.  
IA...NONE.  
NE...NONE.  

 
 

 
 
UPDATE...VANDENBOOGART  
SHORT TERM...DUX  
LONG TERM...DUX  
AVIATION...VANDENBOOGART  
 
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