453
FXUS63 KUNR 121118
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
518 AM MDT SUN APR 12 2026
KEY MESSAGES
- WARM AND MAINLY DRY CONTINUES SUNDAY WITH ISOLATED SHOWERS
- CRITICAL FIRE WEATHER CONDITIONS FOR PARTS OF THE AREA THROUGH
MONDAY, MAINLY ALONG AND SOUTH OF I90
- UPPER TROUGH WILL BRING SOME PRECIP CHANCES TO THE REGION TUE
WITH ADDITIONAL CHANCES TOWARD THE END OF THE WEEK
UPDATE
ISSUED AT 1100 PM MDT SAT APR 11 2026
UPPER AIR SOUTHWEST FLOW CONTINUES ALOFT TONIGHT, WITH A STRONG
SHORTWAVE NOW CROSSING NE WY. WEAK COOL FRONT IS CROSSING THE CWA AT
THIS TIME...WITH GUSTY WESTERLY WINDS INCREASING BEHIND THE FRONT.
SURFACE OBS SHOW WINDS ALREADY INCREASING ACROSS NE THROUGH THE
BLACK HILLS INTO THE NORTHERN/EASTERN FOOTHILLS AND ADJACENT PLAINS.
TEMPS ON SUNDAY WILL NOT BE QUITE AS WARM AS TODAY'S WAS, BUT STILL
WELL ABOVE AVERAGE WITH HIGHS IN THE 70S TO NEAR 80. THESE BREEZY
WESTERLY WINDS WILL CONTINUE THROUGH THE DAY...THEN DECREASE BY
SUNSET. ANOTHER SHORTWAVE WILL CROSS THE REGION SUNDAY NIGHT,
BRINGING ISOLATED SHOWERS TO PORTIONS OF THE AREA. MOST OF IT WILL
BE VIRGA, WITH LITTLE TO NO QPF. A WEAK TROUGH WILL CROSS THE REGION
FOR THE FIRST HALF OF THE WEEK, BRINGING LOW CHANCES OF SHOWERS AND
COOLER (BUT STILL ABOVE AVERAGE) TEMPERATURES.
DISCUSSION
(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 1126 AM MDT SAT APR 11 2026
UPPER TROUGH WILL CONTINUE TO DIG INTO THE WESTERN CONUS, WITH
CONTINUED DOWNSTREAM RIDGING TO THE EAST. THIS WILL SUPPORT WARM
AND MAINLY DRY WEATHER THROUGH MONDAY. ALTHOUGH A FEW ISOLATED
SHOWERS WILL BE POSSIBLE TONIGHT AS A LEAD IMPULSE CROSSES THE
AREA. DRY SW FLOW IS ONGOING ACROSS THE SW FA. AS MIXING AND
PRESSURE FALLS CONTINUE, EXPECT FLOW TO INCREASE THIS AFTERNOON
ACROSS THE SOUTHERN HALF OF THE FA. A LEAD IMPULSE WILL SHIFT THE
LEE-SIDE TROUGH INTO THE FA LATER IN THE AFTERNOON/EVENING. ENOUGH
HIGH LEVEL MOISTURE AND INSTABILITY WILL BE IN PLACE TO FORCE
ISOLATED VERY HIGH BASED SHOWERS AND PERHAPS A FEW TS, ESP OVER NE
WY AND FAR SW SD. GUSTY WINDS WOULD BE EXPECTED WITH ANY
CONVECTION THAT DOES DEVELOP GIVEN INVERTED V PROFILES IN A DEEPLY
MIXED BL. SHOWER ACTIVITY WILL CARRY NORTHEAST THROUGH THE
EVENING. SFC TROUGH WILL PUSH INTO THE AREA AND STALL AS THE MAIN
UPPER TROUGH PUSHES EAST INTO THE ROCKIES. THIS WILL SUPPORT
ANOTHER MILD DAY ACROSS THE REGION SUNDAY WITH HIGHS IN THE 70S, A
FEW LOW 80S IN SCENTRAL SD. DRY SW FLOW CAN BE EXPECTED DUE TO
CONTINUED VERY DRY BL CONDITIONS. THIS PROCESS WILL REPEAT MONDAY
AS THE COOL FRONT WILL BE DELAYED BY THE NEXT SFC LOW EJECTING
INTO REGION. COOL FRONT STARTS TO PROGRESS EAST INTO THE AREA
MONDAY NIGHT WITH INCREASING UPPER LEVEL MOISTURE. THIS COULD
SUPPORT A FEW SHOWERS BY AFTERNOON INTO THE OVERNIGHT HOURS ACROSS
THE NW THIRD. AS THE MAIN UPPER TROUGH MOVES ACROSS THE REGION
TUES, SLIGHTLY BETTER COVERAGE IS ANTICIPATED, BUT LESS THAN
PREVIOUS MODEL RUNS AS THE BULK OF MOISTURE REMAINS SOUTH AND EAST
OF THE FA. HENCE TRENDED POPS DOWN TUE, WITH WED LIKELY DRY. MILD
WEATHER WILL CONTINUE THROUGH THUR AS WAA ENSUES AHEAD OF THE
NEXT UPPER TROUGH WHICH WILL ADVECT ESE IN WESTERLY FLOW OUT OF
THE PAC NW. THIS SYSTEM WILL BRING ANOTHER ROUND OF PRECIP CHANCES
TO THE REGION TOWARD THE END OF THE WEEK, ALTHOUGH CONFIDENCE IN
CHANCES AND AMOUNTS REMAINS LOW GIVEN THE TIME PERIOD.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 515 AM MDT SUN APR 12 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE VALID FORECAST PERIOD.
WEST WINDS WILL CONTINUE TO BE BREEZY ACROSS THE AREA TODAY.
ISOLATED SPRINKLES/SHOWERS LATE THIS AFTERNOON AND EVENING FROM
THE BLACK HILLS WEST COULD BRING BRIEF LOCAL MVFR VISIBILITY,
ALONG WITH ERRATIC WIND GUSTS TO 50 MPH.
FIRE WEATHER
ISSUED AT 1100 PM MDT SAT APR 11 2026
GUSTY SOUTHWEST WINDS, VERY DRY AIR, AND LACK OF APPRECIABLE GREEN
UP WILL SUPPORT CRITICAL FIRE WEATHER CONDITIONS THROUGH MONDAY OVER
PORTIONS OF NORTHEAST WY AND WESTERN SD, MAINLY ALONG AND SOUTH OF
I90. A RED FLAG WARNING REMAINS IN EFFECT THROUGH SUNDAY; HOWEVER,
CRITICAL FIRE WEATHER CONDITIONS ARE LIKELY AGAIN MONDAY AS DRY SW
FLOW CONTINUES ALONG AND SOUTH OF I90 WITH ANOTHER EXTENSION OF THE
RED FLAG WARNING LIKELY NEEDED. A LOW PRESSURE SYSTEM WILL MOVE INTO
THE REGION EARLY NEXT WEEK, POTENTIALLY BRINGING SOME PRECIPITATION
TO THE AREA, ALTHOUGH RAIN CHANCES ARE LOW.
UNR WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR SDZ320>322-
324>326-329-332.
RED FLAG WARNING FROM 11 AM MDT /NOON CDT/ THIS MORNING TO 9 PM
MDT /10 PM CDT/ THIS EVENING FOR SDZ331-333>335.
WY...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ314-315-317.
UPDATE...13
DISCUSSION/KEY MESSAGES...JC
AVIATION...15
FIRE WEATHER...13
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