249
FXUS63 KUNR 211821
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1221 PM MDT WED OCT 21 2026
KEY MESSAGES
- UNSEASONABLY WARM TEMPERATURES THURSDAY AND FRIDAY (10-20F ABOVE
AVERAGE).
- ELEVATED TO NEAR CRITICAL FIRE WX CONCERNS ACROSS MUCH OF THE
AREA FRIDAY AFTERNOON AND EVENING
- MUCH COOLER THIS WEEKEND WITH CHANCES FOR LIGHT RAIN AND
POSSIBLY SOME SNOW SUNDAY.
DISCUSSION
(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 1221 PM MDT WED OCT 21 2026
UPPER LEVEL RIDGE CONTINUES TO INFLUENCE CONDITIONS ACROSS THE
AREA TODAY WITH LIGHT SOUTHERLY FLOW AND WAA SUPPORTING SEASONABLY
WARM TEMPERATURES IN THE UPPER 50S TO LOW 60S. WATER VAPOR
IMAGERY SHOWS SUBTLE SHORTWAVE FEATURE CROSSING THE CWA WITH THE
ONLY IMPACTS BEING SOME MID TO HIGH LEVEL CLOUD COVER MOVING OVER
WESTERN SD. AFTER A MILD NIGHT, RETURN FLOW AND WAA RAMPS UP OVER
THE REGION TOMORROW WITH HIGHS CLIMBING INTO THE UPPER 70S TO LOW
80S ACROSS THE WESTERN SD PLAINS AND NORTHEASTERN WY. RAPID CITY
ITSELF COULD REACH THE LOW 80S, THOUGH HIGH CLOUDS IN THE
AFTERNOON COULD KEEP THINGS SLIGHTLY COOLER. REGARDLESS, IT SHOULD
BE AN UNSEASONABLY WARM DAY ACROSS THE AREA.
NORTHERN STREAM SHORTWAVE MOVES THROUGH THE NORTHERN PLAINS LATE
FRIDAY. SOUTHWEST WINDS WILL PICK UP THROUGH THE DAY FRIDAY AHEAD
OF THE ATTENDANT SFC COLD FRONT WITH GUSTS OF 30-40 MPH OVER MUCH
OF THE WESTERN SD PLAINS AND NORTHEASTERN WY. STRONG WAA THROUGH
THE DAY FRIDAY WILL SUPPORT HIGHS WELL ABOVE AVERAGE (70S TO 80S
ACROSS MUCH OF THE WESTERN SD PLAINS INTO NORTHEASTERN WY). RAPID
CITY COULD BREAK A DAILY RECORD WITH FORECAST HIGHS OF 83
(PREVIOUS RECORDS WERE 82 AND 80 IN DOWNTOWN RAPID CITY AND AT OUR
AIRPORT RESPECTIVELY). THE WARM, DRY, AND WINDY CONDITIONS WILL
SUPPORT ELEVATED TO NEAR CRITICAL FIRE WX CONCERNS FRIDAY
AFTERNOON. SEE FIRE WX DISCUSSION FOR MORE DETAILS.
CURRENT DETERMINISTIC MODEL GUIDANCE SHOWS FRONT WILL PUSH
THROUGH THE REGION LATE FRIDAY NIGHT THROUGH EARLY SATURDAY
MORNING WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE FRONT.
WINDS WILL REMAIN GUSTY THROUGH THE OVERNIGHT HOURS INTO SATURDAY
MORNING WITH MOST RECENT NAM RUNS SHOWING MODEST PRESSURE RISES OF
3-5 MB EARLY SATURDAY MORNING. STRONG CAA AND 850-700MB WINDS OF
30-40KT WILL SUPPORT GUSTY NORTHWEST WINDS, ESPECIALLY OVER
NORTHWESTERN SD.
UPPER LEVEL LOW OVER THE DESERT SW WILL EJECT OVER THE CENTRAL
PLAINS BY SUNDAY. AS THIS LOW LIFTS NORTHEASTWARD AND GRAZES THE
CWA, WE COULD GET A ROUND OF PRECIP SUNDAY AFTERNOON INTO SUNDAY
EVENING. ALL DETERMINISTIC RUNS AND ENSEMBLES HAVE BEEN TRENDING
UPWARDS IN TERMS OF QPF OVER THE AREA SUNDAY. AS FOR WHETHER THIS
QPF WILL BE IN THE FORM OF RAIN OR SNOW, RIGHT NOW IT'S LOOKING
LIKE MOSTLY RAIN OVER THE LOWER ELEVATIONS OF THE PLAINS WITH THE
HIGHER ELEVATIONS IN THE BLACK HILLS BEING COLD ENOUGH FOR SNOW.
IN TERMS OF SNOW: THE MOST RECENT GFS DETERMINISTIC RUNS ARE THE
MOST AGGRESSIVE WITH THIS SYSTEM, SHOWING SEVERAL INCHES OF
ACCUMULATING SNOWFALL OVER THE BLACK HILLS AND PORTIONS OF
SOUTHWESTERN SD AND THE WESTERN SD PLAINS. THE EURO AND CANADIAN
MODELS ARE A BIT MORE CONSERVATIVE AND SHOW LITTLE, IF ANY, SNOW
ACCUMULATION. GIVEN THE RECENT WARM TEMPS AND TIMING OF SNOWFALL
(LOOKING LIKE THIS SHOULD BE IN THE AFTERNOON/EVENING HOURS). ALL
OF THIS TO SAY: AT THIS TIME IT'S NOT LOOKING LIKELY THAT WE'D SEE
MUCH ACCUMULATION EXCEPT FOR IN THE HIGHEST ELEVATIONS OF THE
BLACK HILLS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1124 AM MDT WED OCT 21 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.
MAIN AVIATION CHANGES WILL BE CENTERED AROUND WINDS BUT OVERALL
CONCERNS ARE LOW. INCREASED WIND SPEEDS, UPWARDS OF 10 TO 20 KTS,
ARE LIKELY THROUGH THE TONIGHT FOR NE WY AND NW SD BEFORE A LULL
IN SPEEDS THURSDAY MORNING. WIND SPEEDS INCREASE AGAIN, UP TO 10
TO 15 KTS, FOR MOST OF THE AREA FOR THURSDAY AFTERNOON.
FIRE WEATHER
ISSUED AT 1221 PM MDT WED OCT 21 2026
INCREASING CONFIDENCE IN WIDESPREAD ELEVATED TO NEAR CRITICAL
FIRE WX CONDITIONS OVER MUCH OF THE AREA FRIDAY AFTERNOON AS A
COLD FRONT APPROACHES THE REGION. SOUTHWEST WINDS WILL INCREASE
ACROSS THE REGION FRIDAY MORNING INTO FRIDAY AFTERNOON AHEAD OF
THE FRONT WITH GUSTS OF UP TO 40MPH ACROSS NORTHEASTERN WY.
TEMPERATURES WILL CLIMB INTO THE 70S TO 80S ACROSS MUCH OF THE
WESTERN SD PLAINS AND NORTHEASTERN WY, WELL ABOVE AVERAGE FOR THIS
TIME OF YEAR. AFTERNOON HUMIDITIES WILL DROP INTO THE 20-30%
RANGE ACROSS NORTHEASTERN WY, WESTERN SD PLAINS, AND FOOTHILLS.
THE UNSEASONABLY WARM HIGHS, LOW HUMIDITIES, AND GUSTY SOUTHWEST
WINDS WILL LEAD TO ELEVATED TO NEAR CRITICAL FIRE WX CONCERNS
ACROSS MUCH OF WESTERN SD INTO NORTHEASTERN WY FRIDAY AFTERNOON.
AS OF RIGHT NOW, AM NOT CONSIDERING ANY FIRE WEATHER HEADLINES FOR
FRIDAY AFTERNOON DUE TO HUMIDITIES BEING ABOVE CRITICAL
THRESHOLDS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...WONG
AVIATION...GS
FIRE WEATHER...WONG
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page