086
FXUS63 KUNR 041733
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1133 AM MDT SAT OCT 4 2025
KEY MESSAGES
-A COLD FRONT WILL BRING RAIN, SOME WIND, AND MUCH COOLER
TEMPERATURES TO THE REGION
-GRADUAL WARMING TREND NEXT WEEK AFTER MONDAY, WITH MAINLY DRY
WEATHER
DISCUSSION
(TODAY THROUGH FRIDAY)
ISSUED AT 124 AM MDT SAT OCT 4 2025
UPPER TROUGH NEAR THE GREAT BASIN WILL SHIFT EAST AND PHASE WITH
A DEEP SOUTHERN CANADIAN UPPER TROUGH, FORCING A COLD FRONT INTO
THE AREA, AS A PLUME OF PAC MOISTURE SHIFTS NORTHEAST INTO THE
REGION. COLD FRONT IS PROGRESSING ACROSS THE AREA THIS MORNING
WITH A FEW ELEVATED RETURNS BEGINNING TO SHOW UP ON RADAR OVER
NORTHEAST WY. AS THE UPPER TROUGH SHIFTS EAST, INCREASING LSA WILL
INTERACT WITH A PLUME OF ELEVATED MOISTURE AND SUPPORT INCREASING
COVERAGE OF SHOWERS AND A FEW THUNDERSTORMS THROUGH THE DAY.
HIGHS WILL RANGE FROM THE 60S ACROSS NORTHEAST WY TO AROUND 90
AHEAD OF THE FRONT IN SCENTRAL SD. AS A JET STREAK MOVES INTO THE
REGION FROM THE SOUTHWEST LATE THIS AFTERNOON AND EARLY EVENING,
EXPECT A BROKEN LINE OF HEAVIER SHOWERS AND TS TO PROGRESS ACROSS
THE AREA. THE SOUTHERN END OF THIS FEATURE MAY HAVE SOME GUSTY
WINDS AND SMALL HAIL, BUT OVERALL CAPE IS LIMITED WITH STORMS
MAINLY BEING DYNAMICALLY DRIVEN BY THE SPEED MAX. THE BEST CHANCES
FOR PRECIP WILL BE TONIGHT WHEN THE BEST OVERLAP OF LIFT,
MOISTURE, AND CONVERGENCE SHIFTS OVER THE REGION. GIVEN STRONG
FORCING AND SLOW SYSTEM PROGRESSION PER PHASING, EXPECTING MANY
LOCATIONS ACROSS THE FAR NW TO SEE ONE HALF TO ONE INCH OF RAIN,
WITH THE HIGHER AMOUNTS ACROSS FAR NW SD UNDER THE DEFORMATION
ZONE. BREEZY WINDS WILL DEVELOP SUNDAY MORNING AS THE MAIN COLD
FRONT MOVES THROUGH THE REGION. MODELS HAVE BACKED OFF ON THE
STRONGER WINDS FROM EARLIER, BUT THERE STILL COULD BE A SMALL
WINDOW WHERE A FEW GUSTS OVER 50 MPH WILL ME POSSIBLE ON THE NW SD
PLAINS AND IN THE LEE OF THE BH SUNDAY MORNING. SHOWERS WILL
LINGER INTO SUNDAY PER CYCLONIC FLOW AND UNSTABLE PROFILES, BUT IN
A WANING FASHION. A SECONDARY UPPER TROUGH MAY SUPPORT ANOTHER
ROUND OF LIGHT RAIN OR SNOW ACROSS MAINLY THE SOUTHWEST THIRD
SUNDAY NIGHT INTO MONDAY MORNING. HOWEVER, THE BEST FORCING AND
BETTER MOISTURE LOOKS TO REMAIN SOUTHWEST OF THE FA. PROFILES WILL
CERTAINLY BE COLD ENOUGH FOR SNOW ACROSS THE HIGHER ELEVATIONS OF
THE BH AS WELL AS PORTIONS OF THE WY PLAINS. ANY ACCUMS WOULD BE
VERY LIGHT. MUCH COOLER WEATHER FOR SUNDAY AND MONDAY WITH HIGHS
IN THE 40S/50S ON THE PLAINS AND 30S/40S IN THE BH. UPPER TROUGH
WILL SHIFT EAST OUT OF THE AREA BY TUES WITH UPPER RIDGING
EXPECTED MID WEEK. THIS WILL ALLOW FOR A WARMING TREND AND DRY
WEATHER THEN. ANOTHER COOL FRONT AND ASSOCIATED UPPER TROUGH LOOKS
TO MOVE THROUGH THE AREA BY THE END OF THE WEEK. HOWEVER, THE
DEGREE OF HEIGHT FALLS AND LOCAL EFFECTS REMAINS AT LOW CONFIDENCE
PER CONTINUED LARGE MODEL SPREADS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1130 AM MDT SAT OCT 4 2025
A STORM SYSTEM WILL BRING SHOWERS AND ISOLATED THUNDERSTORMS AS
WELL AS MVFR/IFR CONDITIONS THROUGH THE REST OF THE FORECAST
PERIOD. THE LOWEST CIGS AND HEAVIEST PRECIPITATION WILL BE FOUND
FROM NORTHEAST WY INTO NW SD TONIGHT. WINDS WILL INCREASE FROM THE
NORTHWEST AFTER 06Z, WITH GUSTS OVER 35 KNOTS AS A COLD FRONT
MOVES FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA SUNDAY MORNING.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...JC
AVIATION...SMITH
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