944
FXUS63 KFSD 271724
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1124 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 /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1120 AM CST SAT DEC 27 2025
A BUSY SET OF TAF'S WITH FOG, WIND AND SNOW ALL EXPECTED. WHILE
FOG IS WANING A BIT IN SOUTHWEST MN AND NORTHWEST IA, IT WILL
LIKELY SURGE BACK TO THE NORTHWEST THIS EVENING AHEAD OF AN
INCOMING COLD FRONT. AREAS EAST OF I-29 WILL AGAIN SEE THE BEST
CHANCE FOR VISIBILITIES OF A HALF MILE OR LESS. FROM ROUGHLY 4Z
THROUGH 10Z A STRONG COLD FRONT WILL DROP SOUTHEAST THROUGH THE
AREA. SOME LIGHT MIXED PRECIPITATION WILL BE POSSIBLE AHEAD OF
THIS FRONT, BUT CONFIDENCE IS A BIT LOW ON THIS. HIGHER
CONFIDENCE COMES BEHIND THE FRONT WHERE NORTHWEST WINDS WILL
GUST TO 40 TO 50 MPH LATE TONIGHT THROUGH SUNDAY AFTERNOON AS
WELL AS A BAND OF SNOW EXPECTED LATE TONIGHT THROUGH MID SUNDAY
AFTERNOON. SOME BLOWING SNOW WILL ALSO BE POSSIBLE. WIDESPREAD
MVFR CONDITIONS ARE EXPECTED WITH THE SNOW WITH POCKETS OF IFR
CONDITIONS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...MEYERS
AVIATION...08
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