625
FXUS63 KUNR 130422
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1022 PM MDT SUN APR 12 2026
KEY MESSAGES
-MILD AND MAINLY DRY THROUGH THURSDAY
-CRITICAL FIRE WEATHER CONDITIONS FOR PARTS OF THE AREA THROUGH
MONDAY, MAINLY ALONG AND SOUTH OF I90
-MUCH COLDER AND UNSETTLED FOR THE END OF THE WEEK WITH RAIN AND
SNOW POSSIBLE BY FRIDAY FOR PARTS OF THE AREA
UPDATE
ISSUED AT 1022 PM MDT SUN APR 12 2026
SCATTERED SHOWERS HAVE DEVELOPED ACROSS THE AREA THIS EVENING,
MOST OF THEM HAVE REMAINED FAIRLY WEAK, PRODUCING ONLY LIGHT
PRECIP AND BREEZY TO GUSTY WINDS. ONE OR TWO STRONGER CELLS IN
NORTHWEST SD AND SOUTHEASTERN MT ARE PRODUCING LIGHTNING STRIKES.
THIS ACTIVITY SHOULD MOVE OUT OF THE REGION THROUGH THE OVERNIGHT
HOURS.
FORECAST REMAINS ON TRACK WITH CRITICAL FIRE WEATHER CONDITIONS
EXPECTED TO DEVELOP ACROSS MUCH OF WESTERN SD INTO PORTIONS OF
NORTHEASTERN WY TOMORROW AS TEMPERATURES CLIMB INTO THE 70S TO
80S, RHS DROP INTO THE TEENS, AND WESTERLY WINDS PICK UP AHEAD OF
UPPER LEVEL TROF. CAMS ARE SHOWING SCATTERED PRECIP DEVELOPING
OVER NORTHWESTERN SD TOMORROW AFTERNOON AS IMPULSE MOVES ACROSS
NORTHERN SD/SOUTHERN ND. WHILE BUOYANCY IS MARGINAL (500-1250 J/KG
CAPE PER NAM), 0-6 KM BULK SHEAR VALUES OF 40-60KT COULD SUPPORT
SOME STRONGER CELLS WITH SMALL HAIL HOWEVER, NOT EXPECTING ANY
SEVERE WEATHER.
DISCUSSION
(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 1126 AM MDT SUN APR 12 2026
CENTRAL ROCKIES UPPER TROUGH WILL CONTINUE TO SHIFT EAST WITH
ANOTHER STRONGER TROUGH DROPPING INTO THE PAC NW. THIS WILL
SUPPORT WARM AND MAINLY DRY WEATHER THROUGH MOST OF THUR. DRY SW
FLOW IS ONGOING ACROSS THE SOUTHERN HALF OF THE FA BEHIND A
DEPARTING IMPULSE. A WEAK IMPULSE WILL SHIFT NORTHEAST ACROSS THE
REGION TONIGHT, SUPPORTING ISOLATED SHOWERS ACROSS THE FAR NW.
LIMITED MOISTURE WITH THE BULK OF FORCING REMAINING TO THE NW WILL
HIGHLY LIMITED COVERAGE. FLOW WILL INCREASE MONDAY AHEAD OF THE
MAIN ROCKIES UPPER TROUGH, SUPPORTING VERY DRY BREEZY WEATHER,
PARTICULARLY ACROSS THE SOUTHERN HALF OF THE FA WHERE CRITICAL
FIRE WEATHER CONDS WILL OCCUR. THE ROCKIES TROUGH WILL SPLIT WITH
THE NORTHERN PORTION POSSIBLY SUPPORTING A FEW SHOWERS ACROSS THE
FAR NW MONDAY AFTERNOON/EVENING. HOWEVER, MOST PLACES WILL REMAIN
DRY. COOL FRONT STARTS TO PROGRESS EAST INTO THE AREA MONDAY
NIGHT. THE SOUTHERN PORTION OF THE TROUGH WILL SHIFT EAST TUES,
BARELY SKIRTING THE SOUTHEAST THIRD OF THE FA, WITH MAYBE A SHOWER
OR TWO IN SOUTH CENTRAL SD. CUT POPS TUE AND WED IN LINE WITH
MODEL TRENDS. MILD WEATHER WILL CONTINUE THROUGH THUR AS WAA
ENSUES AHEAD OF THE NEXT UPPER TROUGH WED, WHICH WILL ADVECT SE IN
WESTERLY FLOW OUT OF THE PAC NW. THIS SYSTEM WILL FORCE A STRONG
COLD FRONT INTO THE REGION THUR, WITH STRONG CAA AND WIND
EXPECTED. HOWEVER, THERE IS GROWING INDICATIONS THAT THIS TROUGH
WILL SPLIT, WITH LIMITED PRECIP AMOUNTS OUTSIDE OF PERHAPS
NORTHEAST WY AND MAYBE NW SD, EFFECTIVELY LEAVING MUCH OF WESTERN
SD WITH LITTLE TO NO PRECIP. THINGS QUICKLY THEN WARM BACK UP
EARLY NEXT WEEK AS THE NEXT TROUGH DROPS INTO THE WESTERN CONUS.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 536 PM MDT SUN APR 12 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE VALID FORECAST PERIOD.
ISOLATED SPRINKLES/SHOWERS MAY DEVELOP THIS EVENING FROM THE
BLACK HILLS WEST. ANY SHOWERS WILL BRING BRIEF LOCAL MVFR
VISIBILITY ALONG WITH ERRATIC WIND GUSTS TO 50 MPH.
FIRE WEATHER
ISSUED AT 1126 AM MDT SUN APR 12 2026
GUSTY SOUTHWEST WINDS, EXTREMELY 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 AND HAS
BEEN EXTENDED THROUGH MONDAY. THE MOST CRITICAL AREAS WILL BE
SOUTH OF I90 IN WESTERN SD MONDAY WHERE RH WILL DROP TO 10 PERCENT
WITH WINDS GUSTING TO AROUND 45 MPH IN THE AFTERNOON. A COOL
FRONT WILL DROP INTO THE AREA MONDAY NIGHT WITH WINDS DIMINISHING
AND RH'S RECOVERING. MILD ON TUE AND WED AS AN UPPER LEVEL TROUGH
SKIRTS SOUTH OF THE AREA. A STRONG COLD FRONT WILL MOVE INTO THE
REGION THUR, WITH CHANCES FOR RAIN AND SNOW FRIDAY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ MONDAY FOR
SDZ320>322-324>326-329-331>335.
WY...RED FLAG WARNING UNTIL 9 PM MDT MONDAY FOR WYZ315-317.
UPDATE...WONG
DISCUSSION/KEY MESSAGES...JC
AVIATION...WONG
FIRE WEATHER...JC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page