296
FXUS63 KUNR 211742
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1142 AM MDT SAT MAR 21 2026
KEY MESSAGES
- UNSEASONABLY WARM WITH RECORD HIGHS EXPECTED TODAY.
- COOLER TO START NEXT WEEK WITH SOME LIGHT PRECIP POSSIBLE
TONIGHT INTO SUNDAY.
- MILD AND DRY WEATHER THEN RETURNS MID NEXT WEEK BEFORE ANOTHER
COOL DOWN TOWARD THE END OF NEXT WEEK.
UPDATE
ISSUED AT 1013 AM MDT SAT MAR 21 2026
HAVE EXPANDED THE RED FLAG WARNING TO INCLUDE THE BUTTE COUNTY
AREA THOUGH 9 PM MDT THIS EVENING. THIS AREA WILL BE ONE OF THE
FIRST TO SEE THE COLD FRONT MOVE IN THIS EVENING SUPPORTING
PREDOMINANTLY NORTHERLY WINDS AND EVENTUALLY HIGHER RH VALUES, BUT
IT SEEMS LIKELY THAT THERE WILL BE SOME OVERLAP OF LOW RHS CLOSE
TO 15 PERCENT WITH BREEZY CONDITIONS FOR A FEW HOURS THIS
AFTERNOON, WITH THE HOT TEMPERATURES AND ONGOING REGIONAL DROUGHT
ALSO BEING EXACERBATING FACTORS.
UPDATE ISSUED AT 931 PM MDT FRI MAR 20 2026
THE RED FLAG WARNING CONTINUES OVERNIGHT FOR NORTHEASTERN WYOMING,
THE BLACK HILLS, FOOTHILLS, AND SOUTHWESTERN SOUTH DAKOTA GIVEN
POOR OVERNIGHT RELATIVE HUMIDITY RECOVERY DESPITE LIGHT WINDS.
EXCEPTIONALLY WARM FOR MARCH TOMORROW WITH HIGHS IN THE MID 80S TO
LOW 90S ALONG AND SOUTH OF I-90 WHERE CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED AHEAD OF A COLD FRONT. THIS FRONT WILL
SURGE SOUTHWARD EARLY EVENING SATURDAY, BRINGING GUSTY NORTH WINDS
AND A GRADUAL INCREASE IN RELATIVE HUMIDITY. NO MAJOR CHANGES TO
THE FORECAST OTHER THAN ADJUSTING RFW TO RE-INCLUDE THE FOOTHILLS,
MEADE COUNTY PLAINS, AND HAAKON COUNTY. SPOTTY SHOWERS POSSIBLE
OVERNIGHT SATURDAY INTO SUNDAY MORNING, ALTHOUGH MEAGER LIQUID
AMOUNTS EXPECTED. ELEVATED TO NEAR-CRITICAL FIRE WEATHER
CONDITIONS WITH ABOVE AVERAGE TEMPERATURES SUNDAY THROUGH AT LEAST
NEXT WEEK.
DISCUSSION
(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1113 AM MDT FRI MAR 20 2026
MEAN WESTERN CONUS RIDGE WILL CONTINUE TO SUPPORT UNSEASONABLY
WARM WEATHER THROUGH MUCH OF MID NEXT WEEK. A RIDGE TOPPING
IMPULSE DOES COOL THINGS DOWN SUNDAY AND MONDAY, HOWEVER THINGS
DRY BACK OUT AND WARM UP MID WEEK AS THE RIDGE REBUILDS. WARM AND
DRY WESTERLY FLOW IS ONGOING ACROSS THE AREA. THERMAL RIDGE WILL
SHIFT INTO THE REGION WITH THE WARMEST DAY FOR MOST AREAS EXPECTED
TO BE SAT. A COOL FRONT WILL SAG INTO THE REGION SAT, WITH MOST
GUIDANCE STALLING THIS FEATURE OUT INVOF OF I90 UNTIL EVENING.
AREAS TO THE SOUTH OF THE FRONT WILL DEFINITELY REACH THE LOW 90S,
WITH AREAS ALONG AND JUST TO THE NORTH POTENTIALLY LOSING SOME
MIXING POTENTIAL. DID ADJUST MAX TEMPS FOR THAT. IF THINGS REMAIN
ON TRACK, RECORD HIGH TEMPS WILL LIKELY BE SET AT MANY LOCATIONS
INCLUDING RAPID CITY WHERE THE ALL TIME MARCH HIGHS (85 AND 84 AT
DOWNTOWN AND THE AIRPORT RESPECTIVELY) COULD BE BROKEN AS HIGHS
ARE FORECAST TO REACH THE UPPER 80S TO LOW 90S THERE. RIDGE
TOPPING IMPULSE WILL MOVE THROUGH SAT NIGHT WITH AN ASSOCIATED
COLD FRONT. A PERIOD OF BREEZY NW WINDS ARE EXPECTED SAT EVENING
BEHIND THE FRONT. THIS SYSTEM WILL BRING A FEW SHOWERS TO THE
REGION SAT NIGHT INTO SUNDAY, ESP ACROSS NW SD. UPPER RIDGE THEN
REBUILDS MID NEXT WEEK WITH WARM AND DRY WEATHER RETURNING BEFORE
ANOTHER COOL DOWN OCCURS TOWARD THE END OF THE WEEK PER A STRONG
UPPER TROUGH IN WESTERLY FLOW, ALTHOUGH FORECAST CONFIDENCE LATE
NEXT WEEK IS LOW ATTM.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1136 AM MDT SAT MAR 21 2026
VFR CONDITIONS ARE EXPECTED THROUGH 22/00Z. AFTER 22/00Z BEHIND A
COLD FRONT, AREAS OF MVFR CEILINGS WITH LIGHT RAIN WILL DEVELOP
OVER NORTHEASTERN WY INTO NORTHWESTERN SD ALONG WITH PATCHY LIGHT
RAIN (OR LIGHT SNOW OVER THE BLACK HILLS). THESE CONDITIONS WILL
SHIFT SOUTH AND EAST OVERNIGHT. AREAS OF MVFR CONDITIONS WITH
LIGHT RAIN WILL PERSIST OVER MUCH OF WESTERN SD THROUGH SUNDAY
MORNING, BEFORE LOW CLOUDS AND PRECIPITATION SHIFT TO THE
SOUTHEAST SUNDAY AFTERNOON.
FIRE WEATHER
ISSUED AT 1113 AM MDT FRI MAR 20 2026
VERY DRY, UNSEASONABLY WARM, AND BREEZY CONDITIONS WILL CONTINUE
THROUGH SAT. IN ADDITION, A COLD FRONT WILL MOVE THROUGH SAT
EVENING, SUPPORTING GUSTY NORTH WINDS FOR A PERIOD. GIVEN POOR
RECOVERY TONIGHT WITH EVEN WARMER/DRIER CONDS SAT, HAVE EXTENDED
MOST OF THE CURRENT RED FLAG WARNING INTO SAT EVENING. LEFT THE
NORTHERN EDGE OF ZONES OUT FOR NOW AS A TROUGH WILL SETTLE SOUTH
INTO THE AREA ALONG/NORTH OF I90 AND SUPPORT SLACKENING WINDS. TO
THE SOUTH, BREEZY WINDS ARE EXPECTED WITH WITH WEST WINDS GUSTING
OVER 25 MPH. DID ADD SOUTH CENTRAL SD TO THE RED FLAG WARNING
GIVEN VERY DRY CONDS WITH BREEZY WSW WINDS EXPECTED BY AFTERNOON.
COOLER SUNDAY AND MONDAY, WITH ELEVATED TO CRITICAL FIRE WEATHER
CONDS EXPECTED TO RETURN BY MID NEXT WEEK.
UNR WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
SDZ319>327-329-331>335.
WY...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ314>318.
UPDATE...KSMITH AND M
DISCUSSION/KEY MESSAGES...JC
AVIATION...15
FIRE WEATHER...JC
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