792  
FXUS63 KFSD 202326  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
526 PM CST FRI DEC 20 2024  
   
KEY MESSAGES  
 
- A WEAK SHORTWAVE WILL CONTINUE TO BRING FLURRIES TO LIGHT  
SNOW TO AREAS EAST OF THE JAMES RIVER THROUGH TONIGHT.  
HOWEVER, ACCUMULATIONS WILL VARY BETWEEN A TRACE TO A DUSTING  
WITH UP TO TWO TENTHS OF FRESH ACCUMULATIONS POSSIBLE WITH THE  
HIGHEST ACCUMULATIONS EAST OF I-29.  
 
- MOSTLY QUIET CONDITIONS WILL PERSIST INTO THE NEW WEEK WITH  
ABOVE NORMAL TEMPERATURES RETURNING BY SUNDAY.  
 
- AN ACTIVE PATTERN ALOFT COULD LEAD TO INCREASED PRECIPITATION  
CHANCES FROM THE MIDWEEK ONWARDS.  
 
 
   
DISCUSSION  
 
ISSUED AT 152 PM CST FRI DEC 20 2024  
 
REST OF THE EVENING/TONIGHT: TAKING A LOOK ACROSS THE AREA, THE  
COLD AND DREARY CONDITIONS CONTINUES WITH MOST AREAS SHOWING  
TEMPERATURES IN THE SINGLE DIGITS TO TEENS AS OF 19Z THIS  
AFTERNOON. EXPECT A GRADUAL INCREASE IN TEMPERATURES THROUGH  
THIS EVENING WITH MOST AREAS TOPPING OUT IN THE MID TO UPPER  
TEENS FOR THE DAY. OTHERWISE, THE MAIN STORY CONTINUES TO BE OUR  
LIMITED SNOW CHANCES (<30%) THIS AFTERNOON AND EVENING. TAKING  
A LOOK AT RADAR, A LINE OF BROKEN FLURRIES TO LIGHT SNOW SHOWERS  
EXTENDING ROUGHLY ALONG A BISMARK, ND TO PIERRE TO CHAMBERLAIN  
LINE CONTINUES TO GRADUALLY PROGRESS SOUTHEASTWARDS AHEAD OF A  
QUICK CLIPPER WAVE THIS AFTERNOON WITH THE BETTER RETURNS  
SITUATED IN ND. AT THIS TIME, A DRY SUB-CLOUD LAYER IS KEEPING  
ANY DEVELOPING FLAKES IN CHECK. HOWEVER, AS THIS LINE PROGRESSES  
EASTWARDS TOWARDS THE I-29 CORRIDOR THIS EVENING; BETTER  
SATURATION IN THE LOWER LEVELS OF THE ATMOSPHERE WILL ALLOW FOR  
LIGHT ACCUMULATIONS BETWEEN A TRACE TO A DUSTING WITH UP TO TWO  
TENTHS OF FRESH SNOW POSSIBLE EAST OF THE JAMES RIVER. WITH THIS  
IN MIND, TEMPORARY REDUCTIONS IN VISIBILITY AND A FEW PATCHY  
SLICK SPOTS WILL BE YOUR MAIN IMPACTS WITH MOST OF THIS ACTIVITY  
COMING TO AN END BY 06Z TONIGHT. LASTLY, ANOTHER COLD NIGHT IS  
EXPECTED AS TEMPERATURES FALL INTO THE SINGLE DIGITS TO LOW  
TEENS AS A SURFACE HIGH MOVES OVERHEAD.  
 
SATURDAY & SUNDAY: HEADING INTO THE THE EXTENDED PERIOD, QUIETER  
CONDITIONS RETURN BY SATURDAY AS UPPER-LEVEL RIDGING BEGINS TO  
BUILD. WITH INCREASING WARM AIR ADVECTION (WAA) ALOFT AND THE  
RETURN OF SOUTHERLY SURFACE WINDS, EXPECT TEMPERATURES TO MAKE A  
10-15 DEGREE JUMP TOWARDS OUR SEASONAL NORMALS AS HIGHS TOP OUT  
IN THE 20S AND 30S WITH THE MORE MILD CONDITIONS ALONG THE  
MISSOURI RIVER VALLEY. FROM HERE, WINDS WILL BECOME MARGINALLY  
BREEZY DURING THE AFTERNOON HOURS WITH GUSTS UP TO 25 MPH  
POSSIBLE ESPECIALLY EAST OF THE JAMES RIVER. BY SUNDAY,  
STRENGTHENING WAA AND SOUTHERLY TO SOUTHEASTERLY SURFACE WINDS  
WILL HELP US CONTINUE OUR WARMING TREND AS TEMPERATURES APPROACH  
THE 97.5TH PERCENTILE OF CLIMATOLOGY DURING THE DAY ACCORDING  
TO THE ESAT TABLES. WITH THIS IN MIND, A TEMPERATURE GRADIENT  
WILL SET UP ALONG A HURON TO SIOUX FALLS TO SPENCER, IA LINE  
WITH HIGHS VARYING BETWEEN THE LOW TO UPPER 30S NORTH OF THIS  
LINE AND HIGHS VARYING BETWEEN THE UPPER 30S TO UPPER 40S SOUTH  
OF THIS LINE. FROM HERE, QUASI-ZONAL FLOW ALOFT WILL GUIDE A  
WEAK QUICK-CLIPPER WAVE AND A COLD FRONT ACROSS THE NORTHERN  
PLAINS FROM SUNDAY NIGHT INTO MONDAY. WHILE PRECIPITATION  
CHANCES (<30%) AREN'T COMPLETELY OUT OF THE QUESTION, LIMITED  
SATURATION IN THE DGZ WILL LIKELY KEEP THINGS ISOLATED TO AREAS  
OF FREEZING DRIZZLE AND A FEW FLURRIES AT MOST TO START THE DAY  
ON MONDAY WITH LIMITED ACCUMULATIONS. LASTLY, EXPECT MOST OF  
THIS ACTIVITY TO EXIT THE REGION BY MID MORNING ON MONDAY AS A  
SURFACE RIDGE APPROACHES.  
 
MONDAY ONWARDS: LOOKING INTO THE NEW WEEK, QUIETER CONDITIONS RETURN  
FOR THE WEEK OF CHRISTMAS AS UPPER-LEVEL RIDGING STRENGTHENS ACROSS  
THE REGION. NORTHWESTERLY SURFACE WINDS ALONG WITH LINGERING COLD  
AIR ADVECTION (CAA) ALOFT WILL LEAD TO A SLIGHTLY COOLER BUT ABOVE  
NORMAL DAY ON MONDAY AS HIGHS VARY BETWEEN THE UPPER 20S TO LOWER  
40S WITH THE MILDEST CONDITIONS ALONG THE MISSOURI RIVER VALLEY.  
FROM HERE, THE RETURN OF SOUTHERLY SURFACE WINDS BY TUESDAY WILL  
HELP OUR TEMPERATURES CONTINUE THEIR WARMING TREND THROUGH THURSDAY  
WITH MOST AREAS EXPECTED TO SIT IN THE 30S TO LOW 40S FOR HIGHS.  
LOOKING ALOFT, A PARTICULARLY ACTIVE PATTERN ALOFT IS EXPECTED FROM  
CHRISTMAS DAY ONWARDS AS MULTIPLE SHORTWAVE DIP INTO THE SOUTHERN  
PLAINS AND LIFT INTO THE CENTRAL AND NORTHERN PLAINS THROUGH THE  
WEEKEND. ANY ONE OF THESE WAVES COULD LEADING TO RAIN/SNOW CHANCES  
DEPENDING ON THEIR TIME OF ARRIVAL. HOWEVER, WITH A RANGE OF  
SOLUTIONS AMONG DETERMINISTIC GUIDANCE; ITS A BIT DIFFICULT TO SAY  
WITH ANY CONFIDENCE. WITH THIS IN MIND, MAKE SURE TO KEEP A CLOSE  
EYE ON THE FORECAST ESPECIALLY IF YOU'RE TRAVELING TO VISIT FAMILY  
FOR THE CHRISTMAS AND/OR NEW YEARS HOLIDAYS.  
 
 
   
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/  
 
ISSUED AT 526 PM CST FRI DEC 20 2024  
 
AN AREA OF LIGHT SNOW/FLURRIES WILL SLIDE SOUTHEAST THROUGH  
PORTIONS OF THE FORECAST AREA THIS EVENING, MAINLY NEAR/NORTHEAST  
OF A KHON-KFSD-KSLB LINE. WHILE BRIEF MVFR TO IFR VISIBILITY IS  
POSSIBLE EAST OF TAF LOCATIONS (PERHAPS FOCUSED NEAR KBKX-KSPW),  
VFR CONDITIONS SHOULD BE MOST PREVALENT AS THE SNOW MOVES ACROSS  
THE AREA THROUGH 06Z-08Z.  
 
THEREAFTER, VFR CONDITIONS WILL BE WIDESPREAD, WITH SOUTHEAST  
TO SOUTH WINDS GUSTING 15-25KT NEAR AND EAST OF US HIGHWAY 81  
AFTER 21/16Z.  
 
 
   
FSD WATCHES/WARNINGS/ADVISORIES  
 
SD...NONE.  
MN...NONE.  
IA...NONE.  
NE...NONE.  
 
 
 
 
 
DISCUSSION...GUMBS  
AVIATION...JH  
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