397
FXUS63 KUNR 020427
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1027 PM MDT TUE SEP 1 2026
KEY MESSAGES
- HOT TEMPERATURES WILL RETURN FOR THE SECOND HALF OF THE WEEK,
WITH ABOVE AVERAGE TEMPERATURES. THIS WILL RESULT IN NEAR-
CRITICAL FIRE WEATHER CONDITIONS.
UPDATE
ISSUED AT 912 PM MDT TUE SEP 1 2026
ONLY MINOR ADJUSTMENTS TO THE FORECAST FOR THE OVERNIGHT PERIOD
THROUGH WEDNESDAY. THE MAIN CONCERN OVER THE NEXT 24-72 HOURS WILL
BE INCREASINGLY HOT TEMPERATURES AND NEAR-CRITICAL TO CRITICAL
FIRE WEATHER CONDITIONS, ESPECIALLY ACROSS NE WY.
DISCUSSION
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 142 PM MDT TUE SEP 1 2026
WATER VAPOR IMAGERY SHOWS A STRONG UPPER WAVE LIFTING NE, CROSSING
THE DAKOTAS/EASTERN MT. SURFACE ANALYSIS SHOWS A SURFACE LOW ACROSS
NORTH-CENTRAL WY. LOW LEVEL SE FLOW IS DRAWING INCREASED MOISTURE
ACROSS CENTRAL SD, WRAPPING BACKWARDS TOWARDS THE PLAINS EAST AND
NORTH OF THE BLACK HILLS. DEWPOINTS ARE VARYING WIDELY...FROM THE
40S ACROSS PARTS OF NE WY TO THE 50S OVER FAR WESTERN SD TO AROUND
70 OVER FAR SCENTRAL SD. A DRYLINE BOUNDARY SOUTH OF THE SURFACE LOW
IS EXPECTED TO SLIDE EASTWARD ACROSS SW SD/NEB PANHANDLE LATE THIS
AFTERNOON AND EVENING. THIS LOW LEVEL FORCING WILL COMBINE WITH AN
UPPER WAVE, SUPPORTING THUNDERSTORM DEVELOPMENT. THE BEST
INSTABILITY WILL BE AHEAD OF THE DRYLINE ACROSS SCENTRAL SD, WITH
MLCAPE REACHING 2500 J/KG. SHEAR IS DECENT ENOUGH FOR SUPERCELLS,
WITH LARGE HAIL AND DAMAGING WINDS. FARTHER WEST ACROSS THE SD
PLAINS WHERE HIGHER THETA E AIR HAS DRAWN IN: SOME ISOLATED
THUNDERSTORMS ARE POSSIBLE, BUT NOT ENOUGH INSTABILITY FOR SEVERE
WEATHER. SEVERE STORMS WILL EXIT THE EASTERN BORDER OF THE CWA BY
MID-EVENING BUT COULD SEE LINGERING SHOWERS OVER NE WY/NW SD
LINGERING FOR A FEW MORE HOURS. THEN LOW AMPLITUDE RIDGING SETS UP
ACROSS THE REGION OVERNIGHT INTO WEDNESDAY MORNING, RESULTING IN
STRONG WARM AIR ADVECTION. SUNNY SKIES WILL RETURN AND TEMPERATURES
ARE EXPECTED TO TOP OUT IN THE MID 90S ACROSS PORTIONS OF THE
WESTERN SD PLAINS. TEMPERATURES WELL ABOVE AVERAGE WILL CONTINUE
THROUGH THE END OF THE WEEK...WHICH COULD BE IN THE UPPER 90S
FRI/SAT. WHILE ISOLATED THUNDERSTORMS CAN'T BE RULED OUT MOST DAYS,
THE PATTERN WILL BE GENERALLY DRY FOR THE SECOND HALF OF THE WEEK.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1025 PM MDT TUE SEP 1 2026
MVFR/IFR CEILINGS/VISIBILTY ARE POSSIBLE EAST OF THE BLACK HILLS
TOMORROW MORNING, INCLUDING KRAP, STARTING AROUND 02/13Z AND
LASTING THROUGH 02/16-18Z. VFR CONDITIONS ARE EXPECTED ELSEWHERE
AND BY THE EARLY AFTERNOON. ISOLATED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE OVER NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA
STARTING AROUND 02/21Z AND LAST THROUGH THE REMAINDER OF THE TAF
PERIOD. TRANSIENT MVFR CONDITIONS ARE POSSIBLE AROUND ANY HEAVIER
PRECIPITATION CORES AND GUSTY/ERRATIC WINDS CAN BE EXPECTED WITH
ANY STRONGER CONVECTIVE CORES.
FIRE WEATHER
ISSUED AT 142 PM MDT TUE SEP 1 2026
HOT AND DRY WEATHER RETURNS WEDNESDAY THROUGH THE END OF THE WEEK
WITH NEAR-CRITICAL FIRE WEATHER CONDITIONS EXPECTED. RELATIVE
HUMIDITY MAY BOTTOM OUT AT 10 TO 15 PERCENT ON THURSDAY AND FRIDAY
ACROSS NORTHEASTERN WY AND FAR SOUTHWESTERN SD. IF THE LIKELIHOOD
OF WINDY CONDITIONS INCREASE, THEN CRITICAL FIRE WEATHER
CONDITIONS WILL BE POSSIBLE. WILL CONTINUE TO MONITOR.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...SE
DISCUSSION...13
AVIATION...SCHULTZ
FIRE WEATHER...13
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