369
FXUS63 KUNR 140451
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1051 PM MDT FRI MAR 13 2026
KEY MESSAGES
- LIGHT PRECIPITATION POSSIBLE THROUGH TONIGHT.
- MODERATE TO HEAVY SNOWFALL EXPECTED FOR MUCH OF THE AREA
SATURDAY INTO SUNDAY.
- WARM AND MOSTLY DRY CONDITIONS RETURN FOR NEXT WEEK.
UPDATE
ISSUED AT 936 PM MDT FRI MAR 13 2026
STALLED FRONTAL BOUNDARY ACROSS THE REGION CONTINUES TO SUPPORT AN
FGEN BAND ACROSS NW SD WITH LIGHT SNOW ONGOING THERE. UPSLOPE FOG
IS IN PLACE ALONG THE NORTHERN AND EASTERN FOOTHILLS. LL WINDS ARE
EXPECTED TO RESPOND TO THE APPROACHING UPPER TROUGH, VEERING SE.
THIS SHOULD SUPPORT IMPROVEMENT OF FOG LATER TONIGHT AS DRY AIR
MOVES BACK INTO THE AREA. SFC FRONT WILL SHIFT BACK NORTH SAT,
WITH WARM MILD AREA SPREADING ACROSS THE FAR SOUTHERN FA, WHERE
50S AND 60S ARE EXPECTED. LIGHT SNOW WILL CONTINUE ACROSS FAR NW
SD THROUGH MUCH OF SAT, WITH TEMPS EXPECTED TO REMAIN BELOW
FREEZING. EXPECT 1-2 INCHES OF ACCUMS TONIGHT THROUGH SAT THERE.
COLD FRONT STILL EXPECTED TO MOVE INTO THE REGION SAT AFTERNOON.
HIRES MODELS ARE INDICATING A POTENTIAL SNOW SQUALL SETUP AS A
DYNAMICALLY DRIVEN BAND OF PRECIP IS DEPICTED ADVECTING ACROSS THE
AREA. STEEP LL LAPSE RATES AND STRONG CAA INDICATED ALONG THE
FRONT, WITH AMPLE POST FRONTAL MOISTURE, ALL GOOD INGREDIENTS FOR
THIS. IF A BAND OF SNOW DOES MATERIALIZE, EXPECT A QUICK 1-2
INCHES GIVEN CONVECTIVE COMPONENT. PERHAPS THE ONLY CHANGE FROM
THE PREVIOUS FORECAST IS A DOWNWARD TREND IN SNOW AMOUNTS ACROSS
MUCH OF THE AREA. MAIN BAND OF SNOW WILL DEVELOP EAST OF THE FA
SAT NIGHT WITH GENERALLY LIGHT TO MODERATE SNOW HERE. ALTHOUGH
SNOW AMOUNTS LOOK LESS, STILL EXPECTING AN IMPACTFUL STORM LOCALLY
GIVEN STRONG NORTHERLY WINDS GUSTING OVER 50 MPH, WHICH WILL
SUPPORT AMPLE BLOWING/DRIFTING SNOW AND WHITEOUT CONDS AT TIMES ON
PARTS OF THE SD PLAINS. STILL EXPECTING UPSLOPE SNOW IN THE
NORTHERN BH AND FOOTHILLS, WHICH COULD CERTAINLY SUPPORT DECENT
LOCALIZED AMOUNTS THERE. THINGS DRY OUT SUNDAY, WITH VERY COLD
CONDS SUNDAY NIGHT AS LOWS DROP INTO THE SINGLE DIGITS AT MANY
LOCATIONS. WARMING UP NEXT WEEK WITH MAINLY DRY WEATHER AFTER A
WARM FRONT MOVES THROUGH MONDAY AT WHICH TIME SOME LIGHT PRECIP
WILL BE POSSIBLE
DISCUSSION
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 117 PM MDT FRI MAR 13 2026
NORTHWEST UPPER FLOW CONTINUES OVER THE FORECAST AREA TODAY, AS
MILD TROUGHING SITS OVER THE GREAT LAKES REGION. SURFACE ANALYSIS
SHOWS WARM FRONTAL BOUNDARY RUNNING FROM NORTHEASTERN WY DOWN
INTO SOUTHWESTERN SD THIS AFTERNOON. NORTH OF THE WARM FRONT,
RADAR SHOWS LIGHT PRECIPITATION ONGOING FROM NORTHWEST DOWN INTO
SOUTH CENTRAL SD. WINDS ARE RELATIVELY LIGHT THIS AFTERNOON WITH
TEMPERATURES IN THE 30S TO UPPER 40S.
MID-LEVEL FORCING WILL CONTINUE TO BRING AREAS OF LIGHT
PRECIPITATION OVER THE REGION THROUGH TONIGHT. BEST CHANCE FOR
LIGHT ACCUMULATIONS ARE EXPECTED OVER NORTHWESTERN SD. UPPER
TROUGH THATS CURRENTLY SITTING OVER THE PAC NW COAST WILL TRAVERSE
SOUTHEAST THE REST OF TODAY, MOVING INTO THE NORTHERN PLAINS ON
SATURDAY. STRONG FORCING ASSOCIATED WITH THIS WAVE WILL BRING
MODERATE TO HEAVY PRECIPITATION INTO THE FORECAST AREA STARTING
LATE SATURDAY MORNING IN NORTHWESTERN SD AND OVER SPREADING THE
REGION THROUGHOUT THE DAY. BAROCLINIC ZONE IS EXPECTED OVER THE
FA, AND WILL RESULT IN SOME AREAS IN THE SOUTHERN HALF OF THE AREA
SEEING RAIN TO START OR A RAIN/SNOW MIX, BEFORE TRANSITIONING.
ASSOCIATED COLD FRONT WITH THIS SYSTEM WILL MOVE SOUTH THROUGHOUT
THE DAY, BRINGING ARCTIC AIR BEHIND IT. FRONTOGENESIS BANDING IS
EXPECTED SATURDAY EVENING INTO SUNDAY MORNING. CURRENTLY MODELS
DIFFER A BIT ON WHERE THE HEAVIER BANDING WILL SET UP, BUT
OVERALL CONSENSUS POINTS TO NORTHWESTERN INTO NORTHERN SD, WHERE
4-8 INCHES OF SNOWFALL WILL BE POSSIBLE BETWEEN SATURDAY AFTERNOON
AND SUNDAY MORNING. HAVE ISSUED A WINTER STORM WARNING COVERING
NORTHWESTERN SD AS WELL AS THE NORTHERN AND WYOMING BLACK HILLS
WHERE UPSLOPE ENHANCEMENT IS EXPECTED TO BRING 6-10 INCHES IN THE
HIGHER ELEVATION AREAS. FURTHER SOUTH, A BIT LIGHTER SNOWFALL
ACCUMULATIONS ARE EXPECTED CLOSER TO I-90, HOWEVER STRONG WINDS
WILL ACCOMPANY THE SNOWFALL BEHIND THE FRONT. HAVE ISSUED A WINTER
STORM ADVISORY FOR AREAS ALONG I-90 EAST OF THE BLACK HILLS INTO
SOUTH CENTRAL SD, AS WELL AS PARTS OF THE NORTHEASTERN WY PLAINS
COUNTIES. THESE AREAS CAN EXPECT GENERALLY 2-5 INCHES OF SNOW, BUT
STRONGER WIND GUSTS UP TO 40-50 MPH BEHIND THE COLD FRONT.
PRECIPITATION WILL TAPER OFF FROM WEST TO EAST SUNDAY MORNING INTO
THE AFTERNOON, HOWEVER GUSTY WINDS MAY LINGER A BIT INTO THE EARLY
EVENING HOURS.
LOOKING AHEAD INTO NEXT WEEK, FOLLOWING THIS WINTER SYSTEM UPPER
RIDGING BUILDS OVER THE WESTERN CONUS SUNDAY NIGHT AND STICKS
AROUND FOR MUCH OF NEXT WEEK. THIS WILL RESULT IN MOSTLY DRY
CONDITIONS AND A WARMING TREND. HIGHS BY TUESDAY BOUNCE BACK INTO
THE MID 50S AND 60S, AND LONGER RANGE MODELS POINT TO POTENTIAL
FOR RECORD BREAKING HIGHS LATER IN THE WORK WEEK. THURSDAY AND
FRIDAY LOOK TO BE THE WARMEST DAYS, WHERE HIGHS COULD EVEN REACH
INTO THE 80S FOR SOME AREAS.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1044 PM MDT FRI MAR 13 2026
WIDESPREAD MVFR/IFR CONDITIONS IN LOW CLOUDS AND AREAS OF LIGHT
SNOW WILL CONTINUE ACROSS MUCH OF NORTHEASTERN WY INTO WESTERN SD
THROUGH THE OVERNIGHT HOURS INTO SATURDAY MORNING. CONDITIONS
ACROSS NORTHEASTERN WY AND MOST OF WESTERN SD SHOULD IMPROVE TO
VFR SATURDAY MORNING BUT MVFR/IFR CONDITIONS WILL PERSIST ACROSS
NORTHWESTERN SD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WINTER STORM WARNING FROM NOON SATURDAY TO NOON MDT SUNDAY FOR
SDZ001-002-078.
WINTER STORM WARNING FROM 6 PM SATURDAY TO NOON MDT SUNDAY FOR
SDZ012>014-024-025-032-072-073.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO NOON MDT SUNDAY
FOR SDZ026-030-031-042-076.
WINTER WEATHER ADVISORY FROM 9 PM MDT /10 PM CDT/ SATURDAY TO
NOON MDT /1 PM CDT/ SUNDAY FOR SDZ043-044-046-047-049-077.
WY...WINTER STORM WARNING FROM 6 PM SATURDAY TO NOON MDT SUNDAY FOR
WYZ057-060.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO NOON MDT SUNDAY
FOR WYZ054>056.
UPDATE...JC
DISCUSSION/KEY MESSAGES...DYE
AVIATION...WONG
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