006
FXUS63 KUNR 100424
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1024 PM MDT THU APR 9 2026
KEY MESSAGES
- BREEZY CONDITIONS WILL DEVELOP ACROSS PORTIONS OF NORTHEASTERN
WYOMING AND NORTHWESTERN SOUTH DAKOTA FRIDAY INTO FRIDAY NIGHT,
WITH A FEW GUSTS AS HIGH AS 40 MPH.
- FRIDAY NIGHT HAS TRENDED DRIER, WITH ONLY A 10% CHANCE OF A
LIGHT, LOW-IMPACT RAIN SHOWER AS A WEAK DISTURBANCE MOVES
THROUGH.
- POTENTIAL FOR ELEVATED TO NEAR-CRITICAL FIRE WEATHER CONDITIONS
THIS WEEKEND OVER LARGE PORTIONS OF THE AREA DUE TO GUSTY WINDS,
LOW RELATIVE HUMIDITIES, AND WARM TEMPERATURES IS INCREASING.
AN ISOLATED THUNDERSTORM OR TWO ALSO REMAINS POSSIBLE, WITH LOW
CONFIDENCE.
- THE NEXT CHANCE FOR MEANINGFUL PRECIPITATION ARRIVES MONDAY
INTO TUESDAY, THOUGH AMOUNTS REMAIN UNCERTAIN.
UPDATE
ISSUED AT 1024 PM MDT THU APR 9 2026
NO MAJOR CHANGES TO THE FORECAST WERE NEEDED THIS EVENING. WE
CONTINUE TO EXPECT BREEZY SOUTHEAST WINDS TO DEVELOP FRIDAY
AFTERNOON INTO FRIDAY NIGHT ACROSS PORTIONS OF BOTH NORTHEASTERN
WYOMING (FAVORITE AREA OF THE HREF) AND NORTHWESTERN SOUTH DAKOTA
(FAVORITE AREA OF THE NBM), WITH NBM GUIDANCE CONTINUING TO
SUGGEST A 50-70% CHANCE OF GUSTS EXCEEDING 45 MPH OVER
NORTHWESTERN SD. HOWEVER, THE AREA AT GREATEST RISK FOR THESE PEAK
GUSTS IS RELATIVELY SMALL IN AREAL COVERAGE (SOUTH OF BUFFALO,
WEST OF FAITH, NORTH OF RAPID CITY) WITH PEAK WINDS POTENTIALLY
ONLY GETTING THAT HIGH FOR A FEW HOURS, WHICH GIVES US PAUSE ABOUT
CONSIDERING A WIND ADVISORY (NOT TO MENTION IT WOULD BE A PRETTY
MARGINAL ONE). IN ADDITION, MOST MODEL GUIDANCE IS COMING IN LOWER
THAN THE NBM...HREF ENSEMBLE MAX WIND GUSTS ONLY REACH ABOUT 40
MPH, NOT A SINGLE GFS ENSEMBLE MEMBER GUSTS TO 45 MPH AT BUFFALO
(WITH ECMWF GUSTS EVEN LOWER), AND THE NAM IS PRETTY LIGHT AS
WELL. AS SUCH, WE WILL FORECAST AND MESSAGE THE POTENTIAL FOR A
FEW GUSTS OF 35-40 MPH...OTHERWISE IT'S A TYPICAL BREEZY DAY IN
SOUTH DAKOTA WITH NO ADVISORY CURRENTLY PLANNED. A VERY WEAK
DISTURBANCE MAY STILL BE ABLE TO KICK OFF A COUPLE LIGHT SHOWERS
FRIDAY NIGHT, BUT MOST GUIDANCE HAS TRENDED EVEN DRIER. POTENTIAL
IS NOW ABOUT 10%, WITH ESSENTIALLY NO QPF. MOVING FORWARD AND
WATCHING HIGH TEMPERATURES ON SATURDAY AND SUNDAY...WE CONTINUE TO
NOTE THE NBM 25TH-75TH PERCENTILE RANGE COMING IN ENTIRELY ABOVE
(WARMER THAN) THE DETERMINISTIC NBM (WHICH CAN BE A SIGN THE BLEND
IS STRUGGLING TO "CATCH UP" WITH A PATTERN CHANGE/FAST WARM-UP),
ALTHOUGH OUR BLENDED FORECAST HAS NUDGED A DEGREE OR TWO WARMER
COMPARED TO THIS TIME YESTERDAY, AND RAW MODEL GUIDANCE IS RUNNING
COOLER/CLOSER TO OUR CURRENT FORECAST. THERE MAY ALSO BE SOME
CLOUD COVER RUNNING AROUND WHICH CAN CERTAINLY TAKE THE EDGE OFF
FULL HEATING POTENTIAL. WILL CONTINUE TO STAY THE COURSE WITH OUR
FORECAST AND WATCH TRENDS, BUT THE POTENTIAL REMAINS FOR HIGHS IN
SOME SPOTS TO TOP OUT SEVERAL DEGREES WARMER THAN CURRENTLY
FORECAST...RAPID CITY COULD APPROACH 90 DEGREES AS A HIGH-END
SCENARIO. FINALLY...OVERALL POTENTIAL/CONFIDENCE IS INCREASING IN
CRITICAL FIRE WEATHER CONDITIONS SATURDAY AND SUNDAY DUE TO THE
VERY WARM TEMPERATURES, GUSTY WINDS, AND LOW RELATIVE HUMIDITIES.
RH VALUES WILL BE HIGHEST AND LEAST FAVORABLE OVER THE
NORTHWESTERN SOUTH DAKOTA PLAINS, BUT OVERLAP OF CRITICAL
CONDITIONS (WINDS/RHS) IS POSSIBLE FOR MOST OF THE REST OF THE
REGION FROM NORTHEAST WYOMING, ACROSS THE BLACK HILLS, AND INTO
OUR EAST-CENTRAL AND SOUTHWESTERN SD PLAINS FIRE ZONES. MODELS
CONTINUE TO SUPPORT DECENT INSTABILITY AND THUS AN ISOLATED
THUNDERSTORM CONCERN, BUT LACK OF MOISTURE CONTINUES TO LOOK LIKE
A POTENTIAL LIMITING FACTOR.
DISCUSSION
(THIS EVENING THROUGH THURSDAY)
ISSUED AT 1237 PM MDT THU APR 9 2026
CURRENT UPPER-AIR WATER VAPOR ANALYSIS DEPICTS SPLIT-FLOW ACROSS
CONUS, WITH TROUGHING STRETCHING FROM EASTERN MT TO MI AND SHORT-
WAVE RIDGING LOCATED WITHIN THE TROUGH (OVER MN). THE LOW OVER
NORTHERN ND HAS SHIFTED NORTHEAST, WHILE THE NEXT LOW EXPECTED TO
IMPACT THE REGION (SATURDAY/SUNDAY) IS LOCATED OFF THE NORTHERN
CA/OR COAST. WV IMAGERY INDICATES BANDS OF CLOUD COVER CROSSING THE
REGION WITH RADAR SHOWING LIGHT RETURNS FROM LIGHT RAIN/SNOW SHOWERS
OVER NORTH-CENTRAL SD. CURRENT SURFACE OBSERVATIONS SHOW
TEMPERATURES IN THE 30S AND 40S WITH GENERALLY EASTERLY WINDS OF 10
TO 20 KTS, GUSTING TO 30 KTS. RH VALUES ARE DECREASING ACROSS
SOUTHWESTERN SD AND NORTHEASTERN WY AS DRIER AIR MOVES INTO THE
REGION UNDER RIDGING TO THE WEST.
FRIDAY WILL SEE CONTINUED WARMING AS HIGH PRESSURE AND RIDGING MOVE
OVER THE REGION, ALONG WITH A SLIGHT CHANCE FOR PRECIPITATION FRIDAY
EVENING/NIGHT (<20 PERCENT CHANCE FOR >0.01, NBM CONUS) FOR THE
BLACK HILLS AND SOUTH-CENTRAL SD. WINDY CONDITIONS WILL DEVELOP
FRIDAY AFTERNOON ACROSS NORTHWEST SD WITH CHANCES FOR WIND GUSTS
EXCEEDING 45 MPH (55 TO 75 PERCENT CHANCE, NBM CONUS).
HIGHS SATURDAY AND SUNDAY CREEP INTO THE 80S (55 TO 75 PERCENT
CHANCE SATURDAY/ 30 TO 45 PERCENT CHANCE SUNDAY) ALONG WITH
ELEVATED, POSSIBLY NEAR-CRITICAL, FIRE WEATHER CONDITIONS RETURNING.
RHS WILL BOTTOM OUT AROUND 16 PERCENT SATURDAY AND DROP EVEN LOWER
SUNDAY, DOWN TO 12 PERCENT, ACROSS SOUTHWESTERN SD AND PARTS OF
NORTHEASTERN WY. BREEZY WINDS ARE EXPECTED ACROSS THE SD PLAINS BOTH
DAYS, WHICH MAY WARRANT A RED FLAG WARNING FOR ONE, IF NOT BOTH
DAYS. ALONG WITH THE FIRE WEATHER, THERE WILL BE CHANCES FOR
SHOWERS, AND POSSIBLY A FEW THUNDERSTORMS, SATURDAY
AFTERNOON/EVENING, HOWEVER, AVAILABLE MOISTURE MAY BE LIMITED.
THE NEXT CHANCE FOR MEANINGFUL MOISTURE ARRIVES WITH A TROUGH/LOW
MOVING THROUGH MONDAY/TUESDAY. THE CURRENT NBM-CONUS RUN HAS MUCH OF
WESTERN SD AT A 45 TO 55 PERCENT CHANCE FOR A 0.25 OF AN INCH FROM THE
SYSTEM. HOWEVER, PRECIPITATION AMOUNTS WILL LIKELY BE LOWER DUE
TO THE DRY CONDITIONS THAT HAVE PERSISTED FOR THE REGION.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1024 PM MDT THU APR 9 2026
THE EVENING FORECAST IS ON TRACK WITH WINDS NOW BECOMING VERY
LIGHT AT KRAP AND KGCC. CONFIDENCE REMAINS HIGH IN DRY, VFR
CONDITIONS THROUGHOUT THE TAF PERIOD AS BRIEF SHORTWAVE HIGH
PRESSURE TAKES CONTROL. HIGH-LEVEL CLOUDS WILL INCREASE FROM FEW
TO BKN FROM THE SOUTHWEST FRIDAY AFTERNOON AND EVENING AS A VERY
WEAK DISTURBANCE APPROACHES, ALONG WITH AN INCREASE IN
SOUTHEASTERLY WINDS FRIDAY INITIATING A BIT EARLIER THAN THE
NORMAL DIURNAL CYCLE (STARTING BETWEEN 15-17Z/9-11AM AND
CONTINUING INTO FRIDAY EVENING). EVEN WITH THESE TRENDS,
CONFIDENCE IN VFR CONDITIONS REMAINS HIGH THROUGH SUNSET FRIDAY
NIGHT. OUR NEXT, VERY LOW CHANCE OF SHOWERS (ASSOCIATED WITH THAT
DISTURBANCE WE JUST MENTIONED) CROSSES THE REGION FRIDAY NIGHT
NEAR AND JUST BEYOND THE CURRENT TAF PERIOD, BUT MOST AREAS SHOULD
HOLD DRY WITH TERMINALS THAT DO PICK UP A BRIEF SHOWER SEEING
LITTLE TO NO QPF, AND ABSOLUTELY NO IMPACT ON VSBYS. ALSO STILL
WATCHING A SMALL, LOW-CONFIDENCE CHANCE OF AN ISOLATED
THUNDERSTORM SATURDAY AFTERNOON/EVENING.
FIRE WEATHER
ISSUED AT 1237 PM MDT THU APR 9 2026
ELEVATED TO NEAR-CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
THIS WEEKEND ACROSS SOUTHWESTERN SOUTH DAKOTA AND NORTHEASTERN
WYOMING. HIGHS WILL BE IN THE UPPER 70S TO LOW 80S WITH AFTERNOON
RELATIVE HUMIDITY VALUES FALLING INTO THE TEENS, WITH LOCALLY
LOWER VALUES POSSIBLE SUNDAY. BREEZY WINDS ARE EXPECTED BOTH DAYS,
WHICH MAY LEAD TO PERIODS OF CRITICAL CONDITIONS AND POTENTIAL
RED FLAG CONCERNS. WHILE THERE WILL BE CHANCES FOR LIGHT RAIN
SHOWERS AND ISOLATED THUNDERSTORMS, A WETTING RAIN IS NOT LIKELY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...KSMITH
DISCUSSION/KEY MESSAGES...SCHULTZ
AVIATION...KSMITH
FIRE WEATHER...SCHULTZ
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