004
FXUS63 KUNR 020438
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1038 PM MDT SAT AUG 1 2026
KEY MESSAGES
- HOT SUNDAY WITH HIGHS IN THE 90S AND LOWER 100S ON THE PLAINS.
- ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS SUNDAY INTO
MONDAY.
- STRONG COLD FRONT WILL BRING BREEZY WEATHER MONDAY WITH MUCH
COOLER WEATHER FOR TUESDAY.
- SMOKE FROM WESTERN WILDFIRES EXPECTED SUNDAY NIGHT INTO MONDAY.
UPDATE
ISSUED AT 953 PM MDT SAT AUG 1 2026
NO MAJOR CHANGES TO THE FORECAST WERE NEEDED WITH THIS EVENING'S
UPDATE. LATEST PROJECTED HEAT INDEX VALUES SUNDAY CONTINUE TO
SUPPORT THE CURRENT HEAT ADVISORY ACROSS PORTIONS OF OUR SOUTH
DAKOTA PLAINS WITH NO CHANGES MADE TO TIMING OR AREAS INCLUDED.
STILL EXPECTING AN INCREASE IN WIND AS WELL AS SMOKE ON MONDAY AS
A COLD FRONT CROSSES THE REGION, SETTING US UP FOR HIGH
TEMPERATURES HOLDING IN THE 70S ON TUESDAY!
DISCUSSION
(THIS AFTERNOON THROUGH FRIDAY)
ISSUED AT 1133 AM MDT SAT AUG 1 2026
WESTERN CONUS UPPER RIDGE WILL SHIFT EAST INTO THE NORTHERN
PLAINS AND SUPPORT HOT AND DRY WEATHER AS A STRONGER UPPER TROUGH
MOVES ACROSS THE NORTHERN CONUS. THIS UPPER TROUGH WILL SUPPORT A
STRONG COLD FRONT INTO THE REGION MONDAY, BRINGING A BRIEF MID
WEEK COOL DOWN BEFORE THE HEAT RETURNS. UPPER LEVEL RIDGE WILL
CONTINUE TO TILT INTO THE REGION TODAY AHEAD OF A STRONG SOUTHERN
CANADIAN UPPER TROUGH. THIS WILL WILL SUPPORT WAA AS THE LL
THERMAL RIDGE PUSHES EAST. HAZE FROM MODIFIED WILDFIRE SMOKE WILL
CONTINUE TO IMPACT THE AREA, SUPPORTING ELEVATED POLLUTION LEVELS.
SFC TROUGH WILL ADVECT SE AND SETTLE INTO THE REGION SUNDAY.
BREEZY SOUTHERLY WINDS CAN BE EXPECTED AHEAD THE TROUGH WITH WINDS
SHIFTING NW BEHIND THE TROUGH. CAA WILL BE DELAYED UNTIL EARLY
MONDAY MORNING AS THE MAIN COLD FRONT WILL PUSH INTO THE FA.
HENCE, HOT TEMPS STILL EXPECTED SUNDAY EVEN BEHIND THE TROUGH.
EXPECT THE HOTTEST TEMPS IN SOUTHWEST THROUGH CENTRAL SD WHERE
100-110 WILL BE EXPECTED FOR HIGHS. HEAT ADV AREA STILL LOOKS GOOD
AS DRY AIR WILL LIMIT THE HIGHEST HEAT INDEX READINGS TO THIS
AREA. COLD FRONT WILL MOVE THROUGH EARLY MONDAY WITH WINDS GUSTING
OVER 40 MPH THROUGH MUCH OF MONDAY MORNING ON THE SD PLAINS.
WINDS WILL DECREASE THROUGH AFTERNOON AS THE MAIN PRESSURE RISE
BUBBLE EXITS THE FA. A BATCH OF THICK LOW LEVEL SMOKE IS EXPECTED
TO PUSH THROUGH THE REGION BEHIND THE FRONT SUNDAY NIGHT INTO
MONDAY PER HRRR/RAP FORECASTS. THIS MAY IMPACT VISIBILITY ESP
MONDAY MORNING. CONDS SHOULD IMPROVE THROUGH MONDAY AS THE LL
TRAJECTORIES INDICATE A MORE NORTHERLY AIRMASS ORIGIN. STILL COULD
SEE A FEW SHOWERS AND TS ACROSS MAINLY SCENTRAL SD LATE MONDAY
NIGHT AS THE JET ENTRANCE REGION WILL OVERLAP WITH A WEAK IMPULSE
PASSING TO THE SOUTH OF THE FA, SUPPORTING POTENTIAL ELEVATED
CONVECTION. THIS HAS BEEN TRENDING MORE SOUTH IN RECENT MODEL
RUNS. TEMPS WILL FALL INTO THE 40S AND 50S MONDAY NIGHT WITH A FEW
30S EXPECTED IN PORTIONS OF THE HIGHER BLACK HILLS. HIGHS TUES
WILL BE 10 TO 15 DEGREES BELOW SEASONAL NORMS MAINLY IN THE 70S,
WITH 60S IN THE BLACK HILLS. WESTERN RIDGE WILL REBUILD BEHIND THE
DEEP UPPER LOW SLOWLY PUSHING EAST ACROSS INTERIOR CANADA. THIS
WILL SUPPORT A WARM UP AS SE LL RETURN FLOW ENSUES. EXPECT HIGHS
TO BE BACK IN THE 90S BY THUR. INCREASING LL MOISTURE WILL SUPPORT
ISOLATED TS CHANCES BY WED AS WEAK IMPULSES WILL ADVECT THROUGH
THE REGION IN NW FLOW.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1033 PM MDT SAT AUG 1 2026
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. A FRONT WILL ENTER
THE REGION AFTER ~15Z WITH WINDS SHIFTING FROM THE SOUTH TO
NORTHWEST BEHIND THE FRONT. FRONT WILL STALL OUT OVER SOUTH
CENTRAL SD WITH SOUTHERLY WINDS EXPECTED OVER KICR THROUGH THE
PERIOD. BREEZY WINDS EXPECTED ACROSS THE WESTERN SD PLAINS SUNDAY
AFTERNOON WITH GUSTS OF 25 TO 35KT EXPECTED.
UNR WATCHES/WARNINGS/ADVISORIES
SD...HEAT ADVISORY FROM 10 AM TO 8 PM MDT SUNDAY FOR SDZ013-014-026-
027-030>032-041>044-072>077.
WY...NONE.
UPDATE...KSMITH
DISCUSSION...JC
AVIATION...WONG
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