957  
FXUS63 KFSD 200858  
AFDFSD  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SIOUX FALLS SD  
258 AM CST THU FEB 20 2020  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 251 AM CST THU FEB 20 2020  
 
A COLD NIGHT ACROSS THE REGION THANKS TO MOSTLY CLEAR SKIES AND  
LIGHT WINDS. THAT SAID, WE'RE CLEARLY SEEING THE IMPACT OF SNOW  
COVER ACROSS THE REGION, WITH NEARLY 10 DEGREES OF DIFFERENCE  
BETWEEN AREAS WITH DEEP OR FRESH SNOW COVER AND THOSE WITH MINIMAL  
AMOUNTS. WIND CHILLS ARE HOLDING NEAR OR JUST SHY OF ADVISORY  
CRITERIA THANKS TO THE LIGHT WINDS. MODELS ARE STRUGGLING HOWEVER  
WITH A THIN LAYER OF 900 MB MOISTURE THAT IS PROGGED BASED ON THE  
RAP GUIDANCE TO SLOWLY DRIFT EAST AND SOUTHEAST THIS MORNING.  
 
FOR TODAY, WE'LL BEGIN TO SEE MID-LVL HEIGHTS RISE, AND LOW-LVL WARM  
ADVECTION INTENSIFY. AT THE SURFACE, WINDS WILL TURN MORE SOUTHERLY  
THROUGH THE DAY, HELPING TEMPERATURES CLIMB IN MOST AREAS. IT WILL  
BE A TRICKY TEMPERATURE FORECAST GIVEN FRESH SNOW COVER, AND HAVE  
TRIED TO DRAW IN SLIGHTLY COOLER TEMPERATURES OVER NEW SNOW AND  
IMMEDIATELY DOWNSTREAM FROM THOSE AREAS.  
 
TONIGHT: WINDS REMAIN BREEZY THROUGH THE OVERNIGHT HOURS AND INTO  
FRIDAY MORNING. THE RESULTING DIURNAL CURVE WILL BE MINIMAL, WITH  
TEMPERATURES STEADY OR SLIGHTLY RISING AT TIMES.  
 
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 251 AM CST THU FEB 20 2020  
 
FRIDAY: A WEAK SURFACE BOUNDARY ENTERS THE AREA EARLY FRIDAY, AS THE  
CORE OF THE LOW-LVL THERMAL RIDGE MOVES OVERHEAD. TEMPERATURES  
WILL REBOUND WELL ABOVE NORMAL IN SOME LOCATIONS, WITH AREAS OF  
SOUTH CENTRAL SOUTH DAKOTA CHALLENGING THE 50 DEGREE MARK.  
ELSEWHERE, WILL KNOCK DOWN TEMPERATURES ALONG THE FRESH 3-6" OF  
SNOWPACK ALONG THE HIGHWAY 20 CORRIDOR.  
 
SATURDAY: A WEAK MID-LVL VORTICITY MAXIMUM WILL SLIDE THROUGH  
THE AREA ON SATURDAY, BRINGING AN INCREASE IN MID-LVL CLOUD  
COVER. OTHERWISE THOUGH, ANOTHER DRY DAY WITH WARM TEMPERATURES IS  
EXPECTED. TEMPERATURES WILL CLIMB INTO THE 40S IN MANY LOCATIONS,  
DESPITE THE LIGHT WINDS.  
 
SUNDAY: QUIET WEATHER CONTINUES INTO SUNDAY. MEDIUM RANGE GUIDANCE  
CONTINUES TO SWEEP THE LARGER UPPER TROUGH THROUGH THE CENTRAL  
PLAINS LATER IN THE DAY ON SUNDAY AND SUNDAY NIGHT. THE GFS REMAINS  
THE NORTHERN OUTLIER WITH THIS SOLUTION, AND COULD POSSIBLY  
SPREAD FLURRIES OR LIGHT SNOW THROUGH THE SOUTHERN ZONES. THE  
ECMWF AND GEM HAVE MINIMAL IMPACT FOR THE AREA.  
 
MONDAY-THURSDAY: THERE STILL REMAINS LARGE SCALE DISAGREEMENT WITH  
THE SECONDARY WAVE OF ENERGY DROPPING INTO THE PLAINS FROM THE  
NORTHERN ROCKIES. THE LATEST ECMWF/GEM HOLD MINIMAL IMPACT FOR THE  
AREA, INSTEAD PUSHING THE ENERGY SOUTHWARD ALONG THE WESTERN  
PLAINS AND ONLY BRINGING A COLD AND DRY PUSH OF AIR THROUGH THE  
AREA. THE GFS IS ABOUT THE ONLY MODEL BRINGING SOME IMPACTFUL  
LIGHT SNOW THROUGH THE REGION. FOR RIGHT NOW, WILL MAINTAIN THE  
LOW POPS IN THE FORECAST, BUT COULD SEE THOSE TREND LOWER OVER THE  
UPCOMING 24 HOURS. TEMPERATURES WILL DROP BELOW NORMAL BY THE  
MIDDLE TO END OF NEXT WEEK, BUT NOTHING TOO EXTREME FOR LATE  
FEBRUARY.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 556 PM CST WED FEB 19 2020  
 
VFR CONDITIONS, ALONG WITH VARIABLE WINDS AT OR BELOW 10KT, ARE  
EXPECTED THROUGH THIS FORECAST PERIOD.  
 

 
   
FSD WATCHES/WARNINGS/ADVISORIES
 
 
SD...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR SDZ039-040.  
 
MN...WIND CHILL ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ071-072-  
080-081-090-097.  
 
IA...NONE.  
NE...NONE.  

 
 

 
 
SHORT TERM...DUX  
LONG TERM...DUX  
AVIATION...JH  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab SD Page
The Nexlab IA Page
The Nexlab MN Page
The Nexlab NE Page Main Text Page