016
FXUS63 KUNR 131730
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1130 AM MDT MON APR 13 2026
KEY MESSAGES
-MILD THROUGH THURSDAY
-DRY MOST PLACES OUTSIDE OF NW SD TODAY THROUGH WED
-CRITICAL FIRE WEATHER CONDITIONS, MAINLY ALONG AND SOUTH OF I90
TODAY, AND AGAIN POSSIBLY WEDNESDAY AND ESPECIALLY THURSDAY
-MUCH COLDER AND UNSETTLED FOR THE END OF THE WEEK WITH RAIN AND
SNOW POSSIBLE BY FRIDAY FOR PARTS OF THE AREA
DISCUSSION
(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1055 AM MDT MON APR 13 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. ROCKIES TROUGH
WILL SEMI-SPLIT WITH THE NORTHERN PORTION SUPPORTING A FEW
SHOWERS AND ISOLATED TS ACROSS THE FAR NW THIS AFTERNOON/EVENING.
HOWEVER, THE REST OF THE FA WILL REMAIN DRY. COMPACT JETLET,
ASSOCIATED ENHANCED BULK SHEAR AND MARGINAL CAPE MAY SUPPORT AN
ISOLATED STRONG STORM ON THE SOUTHERN FLANK OF EXPECTED CONVECTION
TODAY, WITH SMALL HAIL AND GUSTY WINDS. COOL FRONT STARTS TO
PROGRESS EAST INTO THE AREA TONIGHT. 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 SOUTHWEST TO SCENTRAL SD.
ENOUGH INSTABILITY MAY BE PRESENT OVER THE BH TO ALSO SUPPORT A
FEW SHOWERS THERE WITH DIURNAL HEATING. SHOWER CHANCES WILL LINGER
INTO WED ACROSS SCENTRAL SD, AS THE TROUGH MOVES FAIRLY SLOW
ACROSS THE CENTRAL PLAINS. 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, THIS TROUGH WILL SPLIT, WITH LIMITED
PRECIP AMOUNTS OUTSIDE OF PERHAPS NORTHEAST WY AND MAYBE FAR SW
SD, EFFECTIVELY LEAVING MUCH OF WESTERN SD WITH LITTLE TO NO
PRECIP. AFTER A COUPLE DAYS BELOW NORMAL, THINGS QUICKLY THEN WARM
BACK UP NEXT WEEK AS THE NEXT TROUGH DROPS INTO THE WESTERN CONUS
AND WAA SPREADS TO ITS EAST.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1128 AM MDT MON APR 13 2026
MAINLY VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. THIS
AFTERNOON, THUNDERSTORMS WILL BE POSSIBLE ACROSS NORTHEAST WY INTO
NORTHWEST SD, MOVING EAST OF THE AREA BY 02Z. HAIL AND STRONG
WINDS ARE POSSIBLE WITH THE THUNDERSTORMS, AND BRIEF MVFR
CONDITIONS MAY BE POSSIBLE IN HEAVIER PRECIPITATION.
FIRE WEATHER
ISSUED AT 1055 AM MDT MON APR 13 2026
GUSTY SOUTHWEST WINDS, EXTREMELY DRY AIR, AND LACK OF APPRECIABLE
GREEN UP WILL SUPPORT CRITICAL FIRE WEATHER CONDITIONS THIS
AFTERNOON MAINLY ALONG AND SOUTH OF I90. A RED FLAG WARNING
REMAINS IN EFFECT INTO THIS EVENING. THE MOST CRITICAL AREAS WILL
BE IN SW SD 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 TONIGHT WITH WINDS DIMINISHING AND RH'S RECOVERING. MILD ON
TUE AND WED AS AN UPPER LEVEL TROUGH SKIRTS SOUTH OF THE AREA.
HOWEVER, LOW RH AND BREEZY WINDS MAY SUPPORT CRITICAL FIRE WEATHER
CONDITIONS ONCE AGAIN ON WED AND ESPECIALLY THUR IN THE SAME
LOCATIONS. A STRONG COLD FRONT WILL MOVE INTO THE REGION THUR,
WITH CHANCES FOR RAIN AND SNOW FRIDAY, MAINLY ACROSS NORTHEAST WY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING UNTIL 9 PM MDT /10 PM CDT/ THIS EVENING FOR
SDZ320>322-324>326-329-331>335.
WY...RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ315-317.
DISCUSSION/KEY MESSAGES...JC
AVIATION...DYE
FIRE WEATHER...JC
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