915
FXUS63 KUNR 131959
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
159 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.
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 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1128 AM MDT FRI MAR 13 2026
MVFR/IFR CONDITIONS CONTINUE IN LIGHT SNOW ACROSS PORTIONS OF NE
WY AND WESTERN SD. PATCHY LIGHT SNOW AND MVFR/IFR CONDITIONS WILL
PERSIST ACROSS PORTIONS OF WESTERN SD PLAINS THIS AFTERNOON, OTHERWISE
VFR CONDITIONS ARE EXPECTED OUTSIDE OF SHOWERS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WINTER STORM WARNING FROM NOON SATURDAY TO NOON MDT SUNDAY FOR
SDZ001-002-014-078.
WINTER STORM WARNING FROM 3 PM SATURDAY TO NOON MDT SUNDAY FOR
SDZ012-013-024-025-032-072-073.
WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ SATURDAY TO
NOON MDT /1 PM CDT/ SUNDAY FOR SDZ026-031-042>044-046-047-
049-076-077.
WY...WINTER STORM WARNING FROM 3 PM SATURDAY TO NOON MDT SUNDAY FOR
WYZ057-060.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO NOON MDT SUNDAY
FOR WYZ054>056.
DISCUSSION/KEY MESSAGES...DYE
AVIATION...SE
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