641
FXUS63 KUNR 221736
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1036 AM MST MON DEC 22 2025
KEY MESSAGES
- TODAY: GUSTY WINDS IN THE FOOTHILLS AND ACROSS PORTIONS OF
NORTHEASTERN WYOMING.
- TODAY: RECORD TO NEAR RECORD HIGHS POSSIBLE.
- THIS WEEK: WINDY, MAINLY DRY AND UNSEASONABLY WARM.
DISCUSSION
(TODAY THROUGH SUNDAY)
ISSUED AT 137 AM MST MON DEC 22 2025
LATEST UPPER LEVEL ANALYSIS SHOWS QUASI-ZONAL FLOW OVER THE
FORECAST AREA, WITH A BUILDING RIDGE OVER THE WESTERN/CENTRAL
CONUS, AND A DEEPENING TROUGH ALONG THE WEST COAST FROM A STRONG
UPPER LOW OFF BRITISH COLUMBIA. AT THE SURFACE, A TROUGH EXTENDS
FROM EAST-CENTRAL WYOMING DOWN THE FRONT RANGE OF THE ROCKIES,
WHILE A WEAK COOL FRONT EXTENDS ACROSS NORTHERN MONTANA INTO
SOUTHEASTERN NORTH DAKOTA. TEMPERATURES AT 0830Z RANGE FROM THE
MID 20S ACROSS NORTHWESTERN SOUTH DAKOTA INTO THE MID 40S ALONG
THE NEBRASKA BORDER. SOUTHWEST WINDS GUSTING TO 35 TO 40 MPH HAVE
BEGUN TO INCREASE ACROSS FAR SOUTHERN CAMPBELL COUNTY.
THE DEEP UPPER LOW OFF THE COAST OF BRITISH COLUMBIA WILL
CONTINUE TO DISLODGE THE WESTERN CONUS RIDGE, SHIFTING IT EASTWARD
OVER THE CENTRAL PLAINS AND EVENTUALLY INTO THE MISSISSIPPI RIVER
VALLEY BY THE END OF THE WEEK. WITH UPPER LEVEL HIGH PRESSURE
ANCHORED OVER THE AREA, UNSEASONABLY WARM TEMPERATURES WILL
CONTINUE THIS WEEK. IMPULSES ROUNDING THE RIDGE WILL BRING BREEZY
TO WINDY CONDITIONS, BUT THE LACK OF AVAILABLE MOISTURE, WILL
LIMIT PRECIPITATION, KEEPING CONDITIONS MOSTLY DRY.
FOR TODAY, THE SURFACE TROUGH OVER EASTERN WYOMING WILL MOVE
EASTWARD INTO WESTERN SOUTH DAKOTA, INCREASING THE PRESSURE
GRADIENT. MODELS INDICATE BOUNDARY LAYER WINDS OF 35-45KT
PERPENDICULAR TO THE BLACK HILLS IN THE SOUTHERN AND HERMOSA
FOOTHILLS ZONES. THEREFORE, THE WIND ADVISORY FOR THOSE ZONES
STILL LOOK GOOD. HAVE DECIDED TO ISSUE A BLOWING DUST HEALTH ALERT
FOR SOUTHERN CAMPBELL COUNTY AS AVERAGE HOURLY WIND SPEEDS AROUND
30 MPH WILL BE COMMON FOR A FEW HOURS TODAY. THE PREFRONTAL WINDS
WILL HELP BRING WARM AIR INTO THE REGION, ALLOWING FOR HIGHS
RANGING FROM THE LOWER/MID 50S ACROSS NORTHWEST SOUTH DAKOTA TO
NEAR 70 DEGREES ACROSS SOUTHWESTERN SOUTH DAKOTA. THESE WARM
TEMPERATURES WILL HAVE THE POTENTIAL FOR RECORD/NEAR RECORD HIGHS
FOR TODAY - KRAP RECORD 65F, GILLETTE 60F, WINNER 68F, CAMP CROOK
58, AND HOT SPRINGS 65. (RECORDS FOR OTHER SITES AVAILABLE ON OUR
LOCAL CLIMATE PAGE).
A WEAK COOL FRONT MOVES THROUGH LATE TODAY AND TONIGHT AS AN IMPULSE
ROUNDS THE UPPER RIDGE. MOISTURE IS LIMITED, SO PRECIPITATION
WILL BE SPARSE, WITH MOSTLY JUST AN INCREASE IN CLOUD COVER. WINDS
WILL SWITCH AROUND TO THE NORTHWEST, BRINGING SLIGHTLY COOLER AIR
INTO THE REGION. THUS, HIGH TEMPERATURES ON TUESDAY WILL BE
SLIGHTLY COOLER THAN TODAY.
WARM AIR ADVECTION RETURNS LATE TUESDAY AS DOES INCREASING
SOUTHWESTERLY FLOW. THUS ANOTHER WARM-UP IS IN STORE FOR THE AREA ON
WEDNESDAY. HIGHS ON WEDNESDAY SHOULD BE SIMILAR TO TODAY WITH 850 MB
TEMPS EXPECTED TO BE AROUND +15F. AGAIN, THIS WILL RESULT IN
RECORD/NEAR RECORD HIGHS AGAIN AND GUSTY SOUTHWESTERLY/WESTERLY
WINDS.
CHRISTMAS WILL LIKELY BE A LITTLE COOLER, BUT STILL MILD, AS ANOTHER
WEAK COOL FRONT MOVES THROUGH CHRISTMAS EVE. MODELS ARE BEGINNING TO
COME INTO LINE SHOWING A STRONGER COLD FRONT MOVING THROUGH THE AREA
IN THE FRIDAY NIGHT/SATURDAY NIGHT TIME FRAME. THIS WOULD BRING DOWN
SOME COLD CANADIAN AIR, GUSTY NORTHWEST WINDS, AND CHANCES FOR SNOW.
AT THIS TIME THE MAIN AREA OF LIFT AND FORCING LOOKS TO REMAIN NORTH
OF THE FORECAST AREA, THUS IMPACTS SHOULD BE BRIEF. ADDITIONALLY,
TEMPERATURES WILL LIKELY JUST DIP TO AROUND 'NORMAL' FOR THIS TIME
OF YEAR.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1034 AM MST MON DEC 22 2025
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. GUSTY WEST TO
SOUTHWEST WINDS WILL BE COMMON ACROSS PORTIONS OF NORTHEASTERN
WYOMING, THE BLACK HILLS, AND SOUTHWESTERN SOUTH DAKOTA THROUGH
23Z TODAY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...WIND ADVISORY UNTIL 3 PM MST THIS AFTERNOON FOR SDZ027-074.
WY...NONE.
DISCUSSION/KEY MESSAGES...SMITH
AVIATION...15
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