212
FXUS63 KUNR 211721
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1121 AM MDT SUN JUN 21 2026
KEY MESSAGES
- SEVERE THUNDERSTORM THREAT RETURNS MONDAY ACROSS NORTHEAST WY,
THE BLACK HILLS, AND SOUTHWEST SD.
- COOLER TEMPERATURES THROUGH TUESDAY, THEN A GRADUAL WARM UP FOR
THE REST OF NEXT WEEK.
DISCUSSION
(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 1043 AM MDT SUN JUN 21 2026
CURRENT UPPER-AIR ANALYSIS AND WATER VAPOR IMAGERY DEPICT ZONAL FLOW
OVER MUCH OF THE CONUS WITH A SHORTWAVE POSITIONED OVER THE DAKOTAS
AND A SURFACE LOW OVER SOUTHERN AB/SK. SATELLITE IMAGERY INDICATES A
VERY MOISTURE-RICH AIR MASS OVER MUCH OF SD WITH DENSE CLOUD COVER
AND FOG ALONG THE EASTERN BLACK HILLS FOOTHILLS, HOWEVER, CLOUD
COVER IS DISSIPATING OVER SOUTHWESTERN SD. RADAR RETURNS SHOW
SHOWERS AND THUNDERSTORMS CONTINUE TO PUSH EAST/SOUTHEAST ACROSS
NORTHWEST, CENTRAL, AND SOUTH-CENTRAL SD. SURFACE OBSERVATIONS SHOW
TEMPERATURES MAINLY IN THE UPPER 50S TO MID 60S, WITH DEW POINTS IN
THE LOW 50S ACROSS NORTHEAST WY AND MID TO UPPER 50S ACROSS WESTERN
SD. WINDS ARE GENERALLY EASTERLY AT 10 TO 18KTS GUSTING TO 26KTS
ACROSS NORTHWEST/WEST-CENTRAL SD, WHILE WINDS ARE NORTHWEST AT 10KTS
GUSTING 18KTS. GUSTY NORTHWEST WINDS UP TO 35KTS WILL BE POSSIBLE
OVER NORTHWESTERN AND SOUTHWESTERN SD AS THE LOW ASSOCIATED WITH THE
SHORTWAVE CONTINUES TO MOVE EAST.
QPF TOTALS THROUGH THIS MORNING HAVE VARIED GREATLY WITH SOME AREAS
RECEIVING OVER 1", MAINLY PARTS OF NORTHWESTERN AND SOUTH-CENTRAL
SD, WHILE AREAS AROUND THE BLACK HILLS AND RAPID CITY AREA RECEIVED
LESS THAN 0.10". IT IS STILL FEAST OR FAMINE WHEN IT COMES TO
RECEIVING MEANINGFUL PRECIPITATION OVER THE REGION.
THUNDERSTORMS AND SHOWERS WILL CONTINUE TO MOVE THROUGH THE REGION
TODAY AS THE SHORTWAVE CONTINUES TO MOVE ACROSS THE REGION. SEVERE
WEATHER IS UNLIKELY TODAY DUE TO THE ENVIRONMENT NEEDING TO RECHARGE
AFTER YESTERDAY'S STORMS. THE LIKELIHOOD OF RECEIVING AT LEAST
ANOTHER 0.25" OF PRECIPITATION THROUGH THE REMAINDER OF TODAY INTO
TOMORROW MORNING IS HIGHEST OVER CENTRAL SD WHERE THERE IS A ~40 TO
55% CHANCE (12Z HREF), WITH LOCALLY HIGHER AMOUNTS POSSIBLE WITH ANY
HEAVIER SHOWERS. THERE IS STILL A CHANCE THAT THE NORTHERN AND
CENTRAL BLACK HILLS COULD PICK UP AT LEAST AN ADDITIONAL 0.10" (~35
TO 45% CHANCE, 12Z HREF), HOWEVER, IT WILL BE ISOLATED TO WHERE
SHOWERS MOVE INTO THE BLACK HILLS AND WON'T BE WIDE-SPREAD.
TEMPERATURES WILL BE COOLER TODAY WITH HIGHS RANGING IN THE 60S TO
LOW 70S.
THIS COMING WEEK WILL START OFF COOLER AND WET AS A COLD FRONT
PUSHES THROUGH, BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
TO THE REGION. SPC CURRENTLY HAS A SLIGHT RISK ISSUED FOR SEVERE
THUNDERSTORMS FOR MOST OF NORTHEAST WY, THE BLACK HILLS, AND FAR
SOUTHWESTERN SD. THE ENVIRONMENT WILL POTENTIALLY SUPPORT A FEW
SUPERCELLS CAPABLE OF PRODUCING +1" HAIL AND +60 MPH WIND GUSTS. THE
12Z RUN OF THE HREF SUGGESTS MEAN SURFACE-BASED CAPE, 0-6KM WIND
SHEAR, AND LAPSE RATES WILL BE COMPARABLE TO SATURDAY, HOWEVER,
FRONTOGENESIS MAY HELP ORGANIZE A FEW STRONGER STORMS. CONFIDENCE
WILL INCREASE WITH SUBSEQUENT MODEL RUNS.
UNSETTLED WEATHER IS EXPECTED TO CONTINUE THROUGHOUT THE REST OF THE
WEEK, WITH PRECIPITATION CHANCES POSSIBLE ON MOST DAYS. TEMPERATURES
WILL GRADUALLY WARM UP THROUGH THE REST OF THE WEEK.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1119 AM MDT SUN JUN 21 2026
WIDESPREAD MVFR-IFR (LOCAL LIFR) CONDITIONS WILL PERSIST ACROSS
PORTIONS OF THE WESTERN SD PLAINS THIS AFTERNOON; TRANSIENT VFR
CONDITIONS POSSIBLE, FROM KRAP INTO SOUTHWESTERN SD AS CLOUDS
THIN. SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE
EVENING HOURS. LOW CLOUDS BUILD BACK INTO THE AREA OVERNIGHT
TONIGHT IFR/LOCAL LIFR IN LOW CLOUDS AND FOG AT KRAP AND WESTERN
SD NEAR THE END OF THE FORECAST PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...SCHULTZ
AVIATION...SE
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