527
FXUS63 KFSD 131737
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1137 AM CST SAT DEC 13 2025
KEY MESSAGES
- SNOWFALL QUICKLY DIMINISHES THROUGH THE AFTERNOON.
- A BRIEF INFLUX OF ARCTIC AIR WILL LEAD TO COLD TEMPERATURES
AND EVEN COLDER WIND CHILLS (AS LOW AS -25 TO -30F) BY SUNDAY
MORNING.
- QUIETER CONDITIONS WITH MILD TEMPERATURES RETURN NEXT WEEK,
THOUGH FRESH SNOWPACK MAY IMPACT HOW QUICKLY TEMPERATURES WARM
EARLY IN THE WEEK.
UPDATE
ISSUED AT 657 AM CST SAT DEC 13 2025
STRONGEST LIFT SEEMS TO HAVE SHIFTED TO NEAR/SOUTH OF US HIGHWAY
20, THOUGH LIGHT SNOW WILL STILL LINGER FOR A FEW MORE HOURS,
TAPERING FROM NORTHWEST TO SOUTHEAST THROUGH NOON. WITH AMOUNTS
LIKELY REMAINING ONLY AROUND AN INCH OR LESS FOR HURON AND INTO
PORTION OF THE SD HWY 34 CORRIDOR, HAVE TRIMMED A FEW COUNTIES
FROM THE NORTHERN PART OF THE ADVISORY.
DISCUSSION
ISSUED AT 318 AM CST SAT DEC 13 2025
TODAY-SUNDAY: SNOW HAS DEVELOPED AS ANTICIPATED OVER THE PAST
2-3 HOURS, MAINLY ALONG/SOUTH OF I-90 ACROSS OUR PORTION OF SD
AS OF 3 AM CST. GREATEST LINGERING UNCERTAINTY IS CENTERED ON
THE NORTHERN EXTENT OF THE MORE IMPACTFUL SNOWFALL THIS MORNING,
WITH A SLIGHT SOUTHWARD SHIFT NOTED IN THE LATEST MODELS. THIS,
IN PART, WOULD BE IN RESPONSE TO A NORTHERLY FLOW OF DRIER AIR
WHICH IS LIMITING INITIAL DEVELOPMENT NORTH OF I-90 EARLY THIS
MORNING. SATELLITE TRENDS ALSO SHOW INDICATIONS OF ENHANCED LIFT
WITH A RELATIVELY NARROW BAND OF COOLING CLOUD TOPS SOUTH OF
I-90/TOWARD MISSOURI RIVER VALLEY.
THIS ENHANCED LIFT ALONG WITH SOUNDINGS SHOWING A DEEP NEARLY
ISOTHERMAL LAYER WITHIN THE DENDRITIC GROWTH ZONE WILL SUPPORT
MODERATE SNOWFALL RATES AROUND 1/2" PER HOUR OR A BIT HIGHER
FOR A FEW HOURS THIS MORNING, WHICH WILL RESULT IN A QUICK 2-4
INCHES OF ACCUMULATION, MAINLY SOUTH OF I-90. WITH UPSTREAM
VISIBILITY STILL AS LOW AS A MILE AT TIMES IN EASTERN MONTANA,
AND 06Z NAM/LATEST RAP/HRRR SHOWING A SECONDARY BAND OF MODERATE
SNOW TOWARD KHON/KFSD AROUND DAYBREAK, AM HESITANT TO TRIM THE
NORTHERN EXTENT OF OUR EXISTING ADVISORY JUST YET. MODELS ARE
CONSISTENT IN TIMING BULK OF THE SNOWFALL OUT OF OUR FORECAST
AREA BY 16-18Z, SO SCHEDULED EXPIRATION OF THE ADVISORY AT NOON
CST STILL LOOKS GOOD.
WEAK COLD ADVECTION ALONG WITH WIDESPREAD CLOUDS/SNOW WILL LIMIT
TEMPERATURE RECOVERY TODAY, WITH HIGHS ONLY IN THE SINGLE DIGITS
TO AROUND 10F. A MODEST NORTHERLY BREEZE 10-20 MPH WILL KEEP
WIND CHILLS BELOW ZERO THROUGH THE DAY, LEADING THE WAY TO A
VERY COLD NIGHT. CLEARING SKIES AND LIGHT WINDS ARE EXPECTED
AS HIGH PRESSURE SLIDES OVER THE REGION. FRESH SNOW COVER WILL
COMPLETE THE TRIFECTA FOR OPTIMAL RADIATIONAL COOLING WITH LOWS
IN THE TEENS BELOW ZERO NEAR/EAST OF THE JAMES RIVER VALLEY. AT
THESE TEMPERATURES, EVEN A SLIGHT BREEZE UNDER 5 MPH WILL PUSH
WIND CHILLS INTO THE 20S BELOW ZERO. VALUES MAY BE MARGINAL IN
SOME LOCATIONS, BUT OVERALL THE EXISTING COLD WEATHER ADVISORY
COVERS THE AREA/TIMING OF GREATEST CONCERN.
SUNDAY WILL AGAIN BRING LIMITED TEMPERATURE RECOVERY MOST OF THE
DAY, ESPECIALLY GIVEN HIGH ALBEDO AS SUNSHINE PREVAILS OVER A
FRESH LAYER OF SNOW. THAT SAID, A STRONG WARM FRONT PUSHES INTO
WESTERN PORTIONS OF THE AREA BY 00Z MONDAY, WITH LATE DAY/EVENING
HIGHS FROM THE SINGLE DIGITS ABOVE ZERO EAST TO THE 20S WEST OF
THE JAMES RIVER. NON-DIURNAL TEMPERATURES WILL RISE THROUGHOUT
SUNDAY NIGHT IN RESPONSE TO THE VERY STRONG WARM ADVECTION AND
BREEZY SOUTH-SOUTHWEST WINDS OVERNIGHT.
MONDAY ONWARD: NORTHWESTERLY FLOW ALOFT CONTINUES OVER AREA
MONDAY AS UPPER LEVEL RIDGE AXIS BUILDS IN THE ROCKIES AND
TROUGH MOVES OFF THE EAST COAST. THIS IS SHORT LIVED AS RIDGE
BREAKS DOWN TUESDAY WITH ZONAL MID LEVEL FLOW THROUGH NEXT WEEK.
GUIDANCE IS QUITE VARIABLE ON THE TIMING/STRENGTH OF ANY WAVES,
BUT MOST GUIDANCE BRINGS A WAVE THROUGH THE NORTHERN PLAINS
MONDAY AND ANOTHER (OR TWO) WEDNESDAY INTO THURSDAY. DETAILS ON
WHERE AND HOW MUCH PRECIPITATION MAY FALL ARE UNCLEAR, BUT MUCH
OF THE WEEK LOOKS TO BE DRY OUTSIDE OF WEDNESDAY/THURSDAY.
PERIODS OF BREEZY TO WINDY CONDITIONS ARE EXPECTED, ESPECIALLY
EARLY MONDAY AND AGAIN MID WEEK.
SOUTHERLY LOW LEVEL FLOW BRINGS MUCH WARMER TEMPERATURES TO THE
REGION EARLY NEXT WEEK, ALTHOUGH UNCERTAINTY EXISTS IN HOW MUCH
WE'LL WARM DUE TO OUR FRESH SNOWPACK. ABOVE AVERAGE TEMPERATURES
ARE EXPECTED WITH HIGH (OVER 80%) CHANCES OF TEMPERATURES ABOVE
FREEZING AREA WIDE ON TUESDAY AND WEDNESDAY, AND HIGH CHANCES
FOR OVER 40F IN SOUTH CENTRAL SD BOTH DAYS. SOUTH CENTRAL SD
EVEN HAS MODERATE (UP TO 60%) CHANCES OF EXCEEDING 50F BY
WEDNESDAY - ALTHOUGH WE'LL HAVE TO SEE HOW QUICKLY WE MELT OUR
SNOWPACK. WE'LL SEE A SLIGHT DECREASE IN TEMPERATURES FOR THE
LATTER HALF OF THE WEEK, BUT STILL WITHIN 5 OR 10 DEGREES OF
SEASONAL AVERAGES.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1134 AM CST SAT DEC 13 2025
SNOW AND MVFR CONDITIONS WILL DIMINISH AND IMPROVE QUICKLY THIS
AFTERNOON FROM NORTH TO SOUTH. SOME PATCHY BLOWING AND DRIFTING
SNOW WILL BE POSSIBLE, BUT THE OVERALL IMPACTS WILL BE MINOR.
OTHERWISE VFR CONDITIONS ARE EXPECTED THE REMAINDER OF THE TAF
PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR SDZ050-052-
057>071.
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO 10 AM CST
SUNDAY FOR SDZ038>040-053>056-059>062-065>067.
MN...COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO 10 AM CST
SUNDAY FOR MNZ071-072-080-081-089-090-097-098.
IA...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ001-012-
013-020>022-031-032.
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO 10 AM CST
SUNDAY FOR IAZ001>003-012>014-021-022-032.
NE...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NEZ013-014.
UPDATE...JH
DISCUSSION...SG/JH
AVIATION...08
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page