017
FXUS63 KUNR 312307
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
407 PM MST SAT JAN 31 2026
KEY MESSAGES
- LIGHT PRECIP OF MOSTLY RAIN SHOWERS WILL CONTINUE TO TAPER AND
END THIS AFTERNOON.
- BREEZY NORTHWEST WINDS ACROSS WESTERN SD AND NORTHEASTERN WY
THIS AFTERNOON AND EVENING PEAK WITH GUSTS OF 35-45 MPH.
- ABOVE AVERAGE TEMPERATURES AND MOSTLY DRY WEATHER CONTINUES
INTO EARLY NEXT WEEK
DISCUSSION
(THIS EVENING THROUGH SATURDAY)
ISSUED AT 200 PM MST SAT JAN 31 2026
TODAY'S PRECIPITATION PLAYED OUT AS FORECAST WITH SNOW LEADING THE
WAY FROM WEST TO EAST. WARMER AIR ORIGINATING OUT OF THE PACIFIC
ATTEMPTED TO SCOUR OUT THE ARCTIC AIR IN PLACE. IT WAS WARM ENOUGH
TO KEEP THE WESTERN HALF OF THE PRECIP FALLING AS FREEZING RAIN
AND EVENTUALLY PLAIN OLD WET DROPS OF RAIN.
THE HEAVIEST PRECIP IS NOW WEST OF THE AREA WITH LIGHT SCATTERED
SHOWERS OF MOSTLY RAIN LINGERING IN WESTERN SOUTH DAKOTA AND A
WINTRY MIX FALLING IN TRIPP CO. AS OF NOON, TEMPERATURES RANGE
FROM LOW 20S IN THE EASTERN FRINGES OF THE CWA TO UPPER 40S IN
CAMPBELL COUNTY, WYOMING. THE PEEKS OF SUNSHINE AND WARM AIR IS A
HARBINGER OF THE FORECAST. EXPECT THE WESTERLY WINDS TO CONTINUE
OVERNIGHT, QUICKEST NORTH AND EAST OF THE BLACK HILLS. DOWNSLOPING
WINDS WILL HELP KEEP MORNING LOWS NEARLY TWENTY DEGREES ABOVE
NORMAL OVERNIGHT WITH SOME OF THE COLDEST LOCATIONS EXPECTED TO BE
THOSE THAT ARE SHELTERED FROM THE WIND AND WITH DEEPEST SNOW
ACCUMULATIONS (E.G. WHITE RIVER VALLEY).
THE SHORTWAVE WORKING ALONG THE CANADIAN BORDER CONTINUES EAST ON
SUNDAY. ITS ATTENDANT 'COLD' FRONT MEANDERS SOUTH THROUGH THE
DAKOTAS BRINGING NEARLY NEUTRAL TEMPERATURE ADVECTION AND
PRODUCING AFTERNOON TEMPS MOSTLY UNCHANGED FROM TODAY. WESTERLY
WINDS WILL BECOME LIGHT OUT OF THE NORTH BY SUNDAY EVENING AS THE
FRONT PASSES THROUGH THE AREA FROM NORTH TO SOUTH BEFORE STALLING
AGAINST THE BLACK HILLS.
MONDAY AND THE WORK WEEK
THE H5 RIDGING CURRENTLY OVER THE WEST COAST NOSES INTO THE HIGH
PLAINS AS ANOTHER SHORT-WAVE CRESTS ITS AXIS ON MONDAY. THE DAY
SHOULD END UP IN THE 40S AND 50S FOR A THIRD CONSECUTIVE DAY FOR
MANY, MAKING QUICK WORK OF REMAINING SNOW PACK.
DETERMINISTIC RUNS OF GFS/EC HAVE BEEN PROGGING THE EJECTING WAVE
INCREASINGLY FARTHER EAST OVER THE PAST 48 HOURS LEAVING ITS
PROJECTED INFLUENCE OVER THE BLACK HILLS WANING. LATEST RUNS OF
THE NBM HAVE REDUCED POPS OVER CENTRAL SOUTH DAKOTA TO UNDER 25%
AND THE BLACK HILLS TO UNDER 15% ON MONDAY EVENING.
BREEZY UPSLOPE NORTHWESTERLY WINDS AND SOME WEAK FORCING FOR
ASCENT (PVA AND JET STREAK DYNAMICS) ACCOUNT FOR THE 35% POPS FOR
THE BLACK HILLS ON TUESDAY EVENING. POPS FOR THIS TIME PERIOD HAVE
BEEN SLIPPING ON THE SD PLAINS (UNDER 15%). QPF LOOKS LIGHT.
MILD TEMPS CONTINUE THROUGH THE REMAINDER OF THE WORK WEEK WITH
THURSDAY CURRENTLY REPRESENTING THE WEEK'S ZENITH. TEMPS MAY PEAK
IN THE 60S WITH THE RIDGE AXIS OVERHEAD AND H8 TEMPS PROGGED AS
WARM AS 10C. RAPID CITY AIRPORT'S WARM RECORDS FOR THE DATE ARE
BOTH IN PERIL: THE WARMEST LOW FOR 2/5 IS 34F IN 1952. OUR
FORECAST HAS 36F DOWNTOWN AND 31F AT THE AIRPORT. THE AFTERNOON'S
FORECAST OF 64 IS ALREADY ONE DEGREE WARMER THAN THE RECORD SET
JUST TWO YEARS AGO (63 | 2024).
GUIDANCE BEGINS TO DIVERGE AT THIS POINT, GENERALLY AGREEING ON
BRISK NORTHWESTERLY H5 FLOW, BUT DISAGREEING ON WHERE TO SET IT
AND ITS ACCOMPANYING SFC BAROCLINICITY. WILL THE COLDER AIR BE
RELEGATED TO AREAS EAST OF THE MISSOURI RIVER OR WILL IT POUR OVER
THE RANCH LAND OF WESTERN SOUTH DAKOTA AND COME TO REST AGAINST
THE BLACK HILLS? IT'S TOO FAR OUT TO BE CONFIDENT.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 407 PM MST SAT JAN 31 2026
VFR CONDITIONS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...NICOLAISEN
AVIATION...JC
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