671
FXUS63 KUNR 261951
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
151 PM MDT TUE MAY 26 2026
KEY MESSAGES
- WARM, BREEZY, AND MOSTLY DRY THIS WEEK SUPPORTING ELEVATED TO
NEAR-CRITICAL FIRE WEATHER CONDITIONS AT TIMES.
- DAILY CHANCES OF THUNDERSTORMS REMAIN LOW/ISOLATED THROUGH
THURSDAY, BEFORE INCREASING FOR FRIDAY, SATURDAY, AND SUNDAY.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 151 PM MDT TUE MAY 26 2026
SYNOPTICALLY-SPEAKING...SOMEWHAT OF A "STAGNANT" WEATHER PATTERN
IS EXPECTED OVER NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA
OVER THE NEXT SEVERAL DAYS AS LONGWAVE RIDGING OVER THE CENTRAL
CONUS LARGELY CONTROLS OUR WEATHER WHILE LONGWAVE TROUGHING WITH A
LARGE/SPRAWLING LOW PRESSURE SYSTEM SPINS TO OUR WEST OVER CA/NV.
THIS WILL SUPPORT CONTINUED WARM TEMPERATURES, DRY AND BREEZY
CONDITIONS LEADING TO ELEVATED TO NEAR-CRITICAL FIRE WEATHER
CONCERNS EACH DAY, AND ONLY A VERY SMALL CHANCE OF A FEW ISOLATED
DIURNALLY-TIMED SHOWERS AND THUNDERSTORMS EACH AFTERNOON/EVENING,
ESPECIALLY WEST IN CLOSER PROXIMITY TO INFLUENCE FROM THE LOW.
OUR POTENTIAL FOR DAILY SHOWERS AND THUNDERSTORMS LOOKS TO
INCREASE QUITE A BIT FRIDAY, SATURDAY, AND SUNDAY AS THE WESTERN
LOW WEAKENS AND GRADUALLY LIFTS NORTHEAST ACROSS THE ROCKIES AS
MORE OF AN OPEN SHORTWAVE TROUGH, RESULTING IN HEIGHT FALLS AND
BETTER ASCENT. A SMALLER-SCALE SURFACE LOW WILL ALSO BE LOCATED
SOUTH OF OUR REGION IN THE PLAINS WEDNESDAY AND THURSDAY, BUT AT
THIS TIME IT MAY BE TOO FAR SOUTH TO HAVE MUCH INFLUENCE ON OUR
LOCAL CONVECTION CHANCES PRIOR TO FRIDAY AND IT THEN LOOKS TO GET
ABSORBED BY THE LIFTING WESTERN LOW (WE'LL HAVE TO KEEP AN EYE ON
HOW FAR NORTH IT MAY DRIFT BEFORE THEN). THE LIFTING WESTERN
LOW/TROUGH WILL BECOME NEGATIVELY-TILTED, PERHAPS SUPPORTING SOME
MORE ROBUST CONVECTION AS WELL AS WE GET INTO THAT FRIDAY-SUNDAY
TIMEFRAME (AN EARLY GLANCE AT LONG-RANGE MODEL SOUNDINGS DO
SUGGEST INCREASING INSTABILITY/CAPE, BUT STILL A LACK OF SHEAR).
FOR TODAY, ADDED LOW-END POPS ACROSS NORTHEAST WYOMING WHERE
SEVERAL OF THE CAMS TRY TO DEVELOP A FEW SHOWERS/THUNDERSTORMS
THIS AFTERNOON AND EVENING, AND SLIGHTLY REDUCED WINDS/WIND SPEEDS
AS NBM GUIDANCE IS COMING IN A BIT EXCITED, ESPECIALLY GIVEN S/SE
FLOW WHICH DOESN'T USUALLY "OVERPERFORM" FOR OUR AREA. FOR NOW,
CHANCES OF THUNDERSTORMS SEEM EVEN LOWER WEDNESDAY COMPARED TO
TODAY AND HELD WITH A DRY FORECAST FOR NOW, WHILE MAKING A
SIMILAR DOWNWARD TWEAK TO WINDS/GUSTS. STILL, BREEZY CONDITIONS
ARE EXPECTED FOR THE NEXT SEVERAL DAYS, AND GUSTS OF 30-40 MPH
WILL BE QUITE COMMON. OVERALL, THUNDERSTORMS ARE NOT EXPECTED TO
BE SEVERE TODAY OR WEDNESDAY, BUT WILL POSE THE USUAL HAZARDS OF
LIGHTNING, LOCALIZED SMALL HAIL, AND GUSTY WINDS WITH ANY STRONGER
CORES.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY)
ISSUED AT 1107 AM MDT TUE MAY 26 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. ISOLATED
SHOWERS/STORMS ACROSS NE WY ARE POSSIBLE AFTER 19-21Z THIS
AFTERNOON; GUSTY, ERRATIC WINDS AND LIGHTNING ARE THE MAIN
THREATS. GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH THE FORECAST
PERIOD.
FIRE WEATHER
ISSUED AT 151 PM MDT TUE MAY 26 2026
WARM, MOSTLY DRY, AND VERY BREEZY CONDITIONS ARE EXPECTED ACROSS
THE REGION THIS WEEK, RESULTING IN ELEVATED TO NEAR-CRITICAL FIRE
WEATHER CONDITIONS. RH VALUES WILL BE THE MAIN WEATHER-DRIVEN
LIMITING FACTOR PRECLUDING RED FLAG CONDITIONS, WITH MINIMUM
VALUES GENERALLY 16-24 PERCENT EACH AFTERNOON (DRIEST TODAY). IN
ADDITION, WE'RE IN THE MIDDLE OF GREEN-UP...SUCH AS IT IS THIS
YEAR...WITH VARYING FUEL CONDITIONS CURRENTLY ACROSS THE FORECAST
AREA. A VERY LOW CHANCE OF A FEW ISOLATED AFTERNOON/EVENING
THUNDERSTORMS WILL ALSO EXIST JUST ABOUT EACH DAY, WITH THE BEST
CHANCES THIS AFTERNOON FOCUSED ACROSS NORTHEASTERN WYOMING WITH
HAZARDS OF LIGHTNING, SMALL HAIL, AND GUSTY/ERRATIC WINDS. SEVERE
THUNDERSTORMS ARE GENERALLY NOT EXPECTED OVER THE NEXT SEVERAL
DAYS. OVERALL RH VALUES MAY MODERATE (RISE) A BIT THIS WEEKEND AS
A TROUGH OF LOW PRESSURE SUPPORTS INCREASED CHANCES OF SHOWERS AND
THUNDERSTORMS (STARTING FRIDAY).
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...KSMITH
AVIATION...SE
FIRE WEATHER...KSMITH
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