408
FXUS63 KFSD 271148
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
548 AM CST SAT DEC 27 2025
KEY MESSAGES
- DENSE FOG WITH VISIBILITY 1/2 MILE OR LESS IS EXPECTED TO
SLOWLY IMPROVE THROUGH THE MORNING. A DENSE FOG ADVISORY
REMAINS IN EFFECT FOR LOCATIONS ALONG AND EAST OF I-29 UNTIL 9
AM THIS MORNING. PATCHY SLICK SPOTS ARE POSSIBLE MAINLY NORTH
OF I-90 AS TEMPERATURES FALL TO NEAR TO BELOW FREEZING.
- ABOVE NORMAL TEMPERATURES TODAY WILL TURN SHARPLY COLDER ON
SUNDAY ACCOMPANIED BY NORTHWEST WINDS GUSTING 30 TO 50 MPH.
SUB-ZERO WIND CHILLS ARE EXPECTED SUNDAY NIGHT THROUGH EARLY
MONDAY.
- LIGHT SNOW IS LIKELY ON SUNDAY. AMOUNTS HAVE TRENDED UPWARDS
UP TO ABOUT 1-2 INCHES WITH ISOLATED HIGHER AMOUNTS UP TO
ABOUT 3 INCHES POSSIBLE EAST OF I-29. THE STRONG WINDS WITH
THE FALLING SNOW WILL LEAD TO SOME BLOWING SNOW ACROSS THE
AREA.
DISCUSSION
ISSUED AT 357 AM CST SAT DEC 27 2025
DENSE FOG PERSISTS GENERALLY ALONG AND EAST OF I-29 EARLY THIS
MORNING. LOW LEVEL FLOW BETWEEN 0-0.5KM IS BEGINNING TO TURN OUT OF
THE SOUTHWEST AND HAS BEGUN ADVECTING DRIER AIR INTO THE AREA. THUS,
AM EXPECTING THE FOG TO CONTINUE TO ERODE AND ALSO PUSH OFF TO THE
NORTHEAST THROUGH THE REST OF THE NIGHT. THE DENSE FOG ADVISORY
REMAIN IN EFFECT THROUGH 9 AM THIS MORNING THOUGH HAVE TRIMMED THE
WESTERN EXTENT OF THE ADVISORY. HOWEVER, WITH TEMPERATURES FALLING
TO NEAR TO BELOW FREEZING NORTH OF I-90, SLICK SPOTS FROM THE FOG IS
POSSIBLE THIS MORNING. ONCE THE FOG PUSHES NORTHEAST/EAST OF THE
AREA MID AND HIGH LEVEL CLOUDS WILL PERSIST FOR THE REST OF THE DAY.
WEAK WARM AIR ADVECTION (WAA) WILL BE IN PLACE WHICH WILL ALLOW HIGH
TEMPERATURES TO REMAIN ABOVE AVERAGE THIS AFTERNOON, WARNING TO THE
40S AND 50S, WARMEST ALONG THE MISSOURI RIVER VALLEY. COULD SEE SOME
REDEVELOPMENT OF FOG AND LOW LEVEL STRATUS LATE THIS AFTERNOON AND
EVENING MAINLY EAST OF I-29. A STRONG COLD FRONT WILL BEGIN TO PUSH
INTO THE AREA DURING THE EVENING HOURS. A STRONG SHOT OF COLD AIR
ADVECTION (CAA) WILL BE DELIVERED TO THE FORECAST AREA IN THE WAKE
OF THIS STRONG FRONT. THIS WILL QUICKLY RAMP UP WINDS OUT OF THE
NORTHWEST WHILE COOLING TEMPERATURES AT A MUCH MORE RAPID RATE.
WINDS LOOK TO GUST UP TO 30-40+ MPH FOR THE OVERNIGHT HOURS,
STRONGEST OVER SOUTH CENTRAL SOUTH DAKOTA.
AT THE SAME TIME, PRECIPITATION WILL BEGIN TO RETURN TO THE AREA VIA
THE ELEVATED FRONT. PRECIPITATION LOOKS TO BEGIN AROUND MIDNIGHT AS
MIXED PRECIPITATION ACROSS CENTRAL AND SOUTH CENTRAL SOUTH DAKOTA DUE
TO INITIAL DRY AIR IN THE MID LEVELS ALONG WITH TEMPERATURES IN THIS
LAYER BEING JUST ABOVE FREEZING. THIS WILL RESULT IN MIXED
PRECIPITATION AS PRECIPITATION BEGINS TO FALL BEFORE THE STRONG LIFT
FROM THE ELEVATED FRONT COOLS PROFILES TO SATURATION, TURNING THE
MAIN PRECIPITATION TYPE TO SNOW. THIS WILL BE DRIVEN BY THE
FRONTOGENESIS (FGEN) BETWEEN ABOUT 850 TO 700 MB. AT THE SAME TIME,
SUFFICIENT OMEGA (UPWARD MOTION) WILL BE PRESENT IN THE DENDRITIC
GROWTH ZONE (DGZ) ON THE ORDER OF ABOUT 15 MICROBARS/SECOND. THIS
WILL BE A QUICK MOVING ROUND OF PRECIPITATION THOUGH AS IT WILL
QUICKLY RACE EASTWARDS THROUGH THE REST OF THE NIGHT AND THROUGH
SUNDAY MORNING.
PRECIPITATION WILL BE JUST ABOUT ALL SNOW FOR THE BEGINNING OF SUNDAY
MORNING. THE SNOW AND THE ASSOCIATED STRONG WIND GUSTS WILL BE
QUICKLY PROGRESSING EASTWARDS THROUGH THE REST OF THE MORNING HOURS.
THE FALLING SNOW AND STRONG WINDS WILL RESULT IN SOME BLOWING SNOW
ACROSS THE AREA. HOW LOW VISIBILITIES WILL GET REMAINS SOMEWHAT
UNCERTAIN AT THIS TIME GIVEN HOW THERE IS LITTLE TO NO SNOW PACK
ACROSS THE MOST OF THE AREA, EXPECT OVER PARTS OF NORTHWEST IOWA AND
SOUTHWEST MINNESOTA. AS ALLUDED TO IN THE PREVIOUS DISCUSSION, THESE
WINDS ARE STILL A GOOD BIT WEAKER THAN OUT PREVIOUS BLOWING SNOW
EVENT. THE BULK OF THE SNOW WILL PUSH EAST OF THE AREA BY ABOUT NOON
THOUGH LIGHT SNOWFALL COULD CONTINUE ACROSS PARTS OF SOUTHWEST
MINNESOTA. IN TERMS OF TOTALS, SNOWFALL AMOUNTS HAVE INCREASED A
LITTLE BIT UP TO 1-2 INCHES WITH ISOLATED HIGHER AMOUNTS UP TO ABOUT
3 INCHES POSSIBLE EAST OF I-29. HOWEVER, DO WANT TO STRESS THAT
THERE REMAINS SOME UNCERTAINTY IN THIS POTENTIAL AS SOME OF THE 00Z
AND 06Z MODELS HAVE COME IN WITH LITTLE SNOWFALL. GIVEN THIS
UNCERTAINTY, HAVE HELD OFF ON ISSUING ANY WINTER RELATED HEADLINES,
BUT WILL SEE WHAT THE 12Z GUIDANCE COMES IN WITH AS WINTER HEADLINES
MAY BE NEEDED IF CONFIDENCE INCREASES.
THE REST OF SUNDAY WILL BE BREEZY IF NOT WINDY WITH GUSTS REMAINING
STRONG AT 40-50 MPH. THIS WILL CONTINUE BLOWING SNOW CHANCES
THROUGHOUT THE DAY ALONG WITH THE POTENTIAL FOR WIND HEADLINES BEING
NEEDED. HIGHS WILL BE MUCH COLDER ON SUNDAY, ONLY WARMING TO THE
UPPER TEENS TO LOW 30S. THE WINDS WILL BE SLOW TO WEAKEN AS THEY
WILL REMAIN BREEZY THROUGH THE NIGHT. WITH LOW TEMPERATURES FALLING
TO THE SINGLE DIGITS THIS WILL MAKE FOR COLD WIND CHILLS DOWN TO
ABOUT -10F TO -20F SUNDAY NIGHT.
MONDAY WILL BE A COLD DAY WITH A COLD SURFACE HIGH IN PLACE. HIGHS
WILL ONLY WARM TO THE TEENS WITH LOWS FALLING TO THE SINGLE DIGITS
OVERNIGHT. TUESDAY WILL SEE A BRIEF WARM UP WITH HIGHS WARMING BACK
TO THE 30S AND 40S BEFORE TEMPERATURES TREND BACK TO NEAR SEASONABLE
FOR THE REST OF THE WEEK.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 547 AM CST SAT DEC 27 2025
LATEST SATELLITE AND SURFACE OBSERVATIONS SHOW THAT FOG AND STRATUS
HAS BEEN ERODING AND PUSHING OFF TO THE EAST/NORTHEAST. VISIBILITIES
AND CEILINGS REMAIN VARIED FROM VFR ALL THE WAY DOWN TO LIFR IN FOG.
THE EXCEPTION IS LOCATIONS SOUTH OF HIGHWAY-20, CLOSER TO KTQE AND
KHNR WHERE FOG AND STRATUS HAS BEGUN EXPANDING INTO. HAVE INCLUDED A
TEMPO GROUP FOR FOG AT KSUX AS THE LOW LEVEL FLOW SHOULD ADVECT THE
FOG INTO OR NEAR KSUX OVER THE NEXT FEW HOURS.
THE GOOD NEWS IS THAT FOG AND STRATUS WILL LARGELY COME TO AN END
THROUGH THE MORNING HOURS, LEAVING MID AND HIGH LEVEL CLOUDS ALONG
WITH LIGHT SOUTHERLY WINDS FOR MOST OF THE MORNING AND INTO THE
AFTERNOON HOURS. A COLD FRONT WILL BE PUSHING INTO THE AREA THIS
EVENING, TURNING WINDS TO OUT OF THE NORTHWEST AND QUICKLY
STRENGTHENING. GUSTS UP TO 20-35 KNOTS IS EXPECTED THROUGH THE
NIGHT. AT THE SAME TIME, PRECIPITATION WILL BE DEVELOPING ACROSS
CENTRAL AND SOUTH CENTRAL SOUTH DAKOTA LATE THIS EVENING BEFORE
PUSHING INTO THE AREA TONIGHT. PRECIPITATION WILL BE LARGELY SNOW
THOUGH SOME RAIN CAN MIX IN DURING THE INITIAL ONSET. CEILINGS AND
VISIBILITIES WILL BE ON THE DECLINE, CURRENTLY FAVORED DOWN TO
MVFR/IFR LEVELS. THE SNOW AND STRONG WINDS WILL FINISH OUT THE TAF
PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR SDZ040-055-
056-061-062-066-067-071.
MN...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ071-072-
080-081-089-090-097-098.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ001>003-
012>014-020>022-031-032.
NE...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NEZ014.
DISCUSSION...MEYERS
AVIATION...MEYERS
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