040  
FXUS63 KUNR 090329  
AFDUNR  
 
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY  
NATIONAL WEATHER SERVICE RAPID CITY SD  
829 PM MST THU DEC 8 2022  
   
UPDATE
 
 
ISSUED AT 826 PM MST THU DEC 8 2022  
 
LATEST WATER VAPOUR LOOP DEPICTED LOW NEAR KONL WITH TIGHT BAND  
OF SNOW WRAPPING AROUND IT INTO SOUTH-CENTRAL SD. BEST LIFT IS  
SHIFTING EASTWARD PER IR/RADAR LOOPS. THIS IS INLINE WITH  
KRAP/HRRR GUIDANCE AS WELL AS HIGHWAY CAMS. THUS, HAVE LET WINTER  
WEATHER ADVISORY EXPIRE ON-TIME FOR PART OF SOUTHERN SD AND  
EXPECTED THE REST WILL EXPIRE ON/BEFORE 06Z. REST OF FORECAST IN  
GOOD SHAPE.  
 

 
   
DISCUSSION
 
(THIS EVENING THROUGH THURSDAY)  
ISSUED AT 228 PM MST THU DEC 8 2022  
 
NEAR ZONAL FLOW IN THE UPPER LEVELS HAS DEVELOPED ACROSS THE  
REGION, WHILE A COMPACT UPPER LOW EMBEDDED IN THE FLOW PUSHES  
EASTWARD ACROSS CENTRAL NEBRASKA. JUST NORTH OF THE LOW CENTER,  
STRONG FORCING IS BRINGING A BAND OF SNOW TO SOUTHWEST SD, AND  
BEGINNING TO TRANSITION INTO SOUTH CENTRAL SD. KUDX RADAR SHOWS  
MODERATE TO HEAVY SNOW FROM OELRICHS TO MARTIN TO MISSION. SURFACE  
OBS AND WEBCAMS ACROSS FALL RIVER COUNTY SHOW SNOWFALL NOT  
ACCUMULATING BECAUSE OF TEMPS JUST ABOVE FREEZING. THE EXCEPTION  
IS TOWARD THE FAR SE CORNER OF THE COUNTY ALONG THE NEBRASKA  
BORDER NEAR HWY 385 WHERE SNOW IS BEGINNING TO ACCUMULATE. GIVEN  
THE MAJORITY OF THE COUNTY HAS LITTLE TO NO SNOW ACCUMULATION,  
HAVE CANCELLED THE ADVISORY. OTHERWISE ANOTHER TWO TO FOUR INCHES  
OF SNOW IS EXPECTED THROUGH THIS EVENING ACROSS THE REST OF THE  
ADVISORY AREA. DRY WEATHER WILL RETURN TO THE REGION TOMORROW AND  
CONTINUE THROUGH SUNDAY. A SHORTWAVE TROUGH WILL CROSS THE AREA  
FRIDAY NIGHT, BUT THE AIR LOOKS TOO DRY IN THE LOW/MID LEVELS FOR  
ANY PRECIP TO DEVELOP. WEAK UPPER RIDGING WILL BRING QUIET WEATHER  
TO THE AREA SATURDAY AND SUNDAY, WITH TEMPERATURE NEAR OR JUST  
ABOVE AVERAGE. THEN THE NEXT SYSTEM APPROACHES, WHICH IS BEGINNING  
TO GET A LOT OF ATTENTION. MODELS IN GENERAL ARE SHOWING A STRONG  
UPPER LOW ACROSS THE WESTERN CONUS EARLY NEXT WEEK, THEN WILL  
BECOME NEGATIVELY TILTED ACROSS THE CENTRAL CONUS, THEN HAVE VERY  
LITTLE MOVEMENT THROUGH MUCH OF THE WORK WEEK. THERE IS HIGH  
CONFIDENCE THAT THIS STORM WILL BRING SNOW TO WIDE SWATHS OF THE  
NORTHERN GREAT PLAINS...AND SOME LOCATIONS MAY GET SIGNFICANT  
AMOUNTS OF SNOW. HOWEVER, THERE IS STILL LOW CONFIDENCE ON WHERE  
THESE LOCATIONS ARE. IT IS POSSIBLE OUR CWA WILL SEE SOME OF THESE  
VERY HIGH ACCUMULATIONS, BUT IT'S STILL EARLY ENOUGH THAT WE  
EXPECT TO SEE CHANGES IN MODEL SOLUTIONS OVER THE NEXT SEVERAL  
DAYS. THIS IS ESPECIALLY TRUE BEFORE SUNDAY, WHEN THE SYSTEM IS  
EXPECTED TO COME ONSHORE. ONLY THEN CAN BETTER DATA SAMPLING BE  
OBTAINED FROM RADIOSONDE BALLOON LAUNCHES. IN THE 12Z RUN, THE  
ECMWF AND CANADIAN MODELS SHOW THE HEAVIEST SNOW AMOUNTS SLIGHTLY  
FARTHER EAST THAN PREVIOUS RUNS, AND WE EXPECT TO SEE MORE  
VARIATIONS IN SOLUTIONS THROUGH THE WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)  
ISSUED AT 424 PM MST THU DEC 8 2022  
 
MVFR/IFR CONDITIONS EXPECTED ACROSS FAR SOUTHWEST INTO SOUTH-  
CENTRAL SD THROUGH 06Z DUE TO LOW CLOUDS/SNOW. CONDITIONS WILL  
IMPROVE FROM WEST TO EAST OVERNIGHT. OTHERWISE (INCLUDING  
KRAP/KGCC), VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.  
 

 
   
UNR WATCHES/WARNINGS/ADVISORIES
 
 
SD...WINTER WEATHER ADVISORY UNTIL 11 PM MST /MIDNIGHT CST/ THIS  
EVENING FOR SDZ044-047-049.  
WY...NONE.  

 
 

 
 
UPDATE...HELGESON  
DISCUSSION...13  
AVIATION...HELGESON  
 
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