653
FXUS63 KFSD 260941
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
341 AM CST FRI DEC 26 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 THE JAMES
RIVER 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 THROUGH SATURDAY TURN SHARPLY COLDER
SUNDAY ACCOMPANIED BY NORTHWEST WINDS GUSTING 30 TO 45 MPH.
SUB-ZERO WIND CHILLS ARE EXPECTED SUNDAY NIGHT THROUGH EARLY
MONDAY.
- LIGHT SNOW IS POSSIBLE ON SUNDAY THOUGH AMOUNTS ARE FAVORED TO
REMAIN BELOW AN INCH AT THIS TIME.
DISCUSSION
ISSUED AT 341 AM CST FRI DEC 26 2025
DENSE FOG PERSISTS ACROSS THE AREA EARLY THIS MORNING. STARTING TO
SEE SOME EROSION ON THE WESTERN SIDE OF THE FOG AS A WEAK FRONT
PUSHES INTO THE AREA. THE FRONT AND ASSOCIATED WEAK COLD AIR
ADVECTION (CAA) LOOKS TO PUSH THE FOG FURTHER EASTWARDS, PRIMARILY
ALONG AND EAST OF THE JAMES RIVER. DESPITE THE WEAK CAA IN PLACE,
SOUNDINGS CONTINUE TO SHOW THAT A STOUT INVERSION ABOVE THE FOG
LAYER WILL REMAIN ALOFT FOR TODAY. ON TOP OF THAT, 0-0.5KM WINDS ARE
OUT OF THE NORTHWEST THIS MORNING BUT WILL TURN BACK TO OUT OF THE
SOUTH THIS AFTERNOON AS A WEAK SURFACE HIGH PUSHES THROUGH THE AREA.
THUS, THINK THAT FOG AND LOW LEVEL STRATUS WILL REMAIN FOR THE DAY
TODAY THOUGH DO THINK THAT THE FOG WILL PREDOMINATELY LIFT TO LOW
LEVEL STRATUS BY THE LATE MORNING TO AFTERNOON TIMEFRAME. LOCATIONS
EAST OF THE JAMES RIVER, AND ESPECIALLY ALONG AND EAST OF I-29 ARE
MOST LIKELY TO SEE THIS CONTINUATION OF FOG AND STRATUS AS THE BEST
0-0.5KM HUMIDITY/MOISTURE WILL RESIDE IN THIS AREA. THAT SAID, HAVE
LEFT THE CURRENT DENSE FOG ADVISORY IN PLACE TO ACCOUNT FOR THE
POTENTIAL THAT NEW FOG DEVELOPS ON ITS WESTERN FRINGES. HAVE LEFT
THE TIME FRAME THE SAME WITH THE ADVISORY EXPIRING AT 9 AM. TRENDS
WILL BE MONITORED THROUGH THE MORNING HOURS AND ADJUSTMENTS TO THE
HEADLINE WILL BE MADE AS NECESSARY. COULD ALSO SEE SOME SLICK SPOTS
OUT THERE MAINLY NORTH OF I-90 WHERE TEMPERATURES WILL LOWER TO NEAR
TO JUST BELOW FREEZING. AT THE SAME TIME, HAVE LOWERED HIGHS DOWN
TO THE UPPER 30S, 40S, AND EVEN 50S TO ACCOUNT FOR THE PERSISTENT
CLOUD COVER AND FOG. TEMPERATURES WILL NOT MOVE A WHOLE LOT DURING
THE DAY, EXCEPT FOR LOCATIONS ACROSS SOUTH CENTRAL SOUTH DAKOTA
WHERE LITTLE IF ANY FOG AND STRATUS IS EXPECTED. THIS IS ALSO THE
SAME AREA THAT WILL SEE HIGHS WARM TO THE 50S. THUS, LOW
TEMPERATURES WILL FALL TO THE 30S OVERNIGHT. REMAINING STRATUS LOOKS
LOOKS TO DROP BACK DOWN TO FOG FOR LOCATIONS MAINLY NEAR AND EAST OF
A HURON SOUTH DAKOTA, TO FREEMAN SOUTH DAKOTA, TO SIOUX CITY, IOWA
LINE TONIGHT BUT THE 0-0.5 KM WIND WILL START TAKING ON A WESTERLY
COMPONENT WHICH SHOULD FINALLY CLEAR OUT THE REMAINING FOG AND
STRATUS OVERNIGHT.
WITH LOW LEVEL FLOW CONTINUING TO HAVE A WESTERLY COMPONENT TO IT,
SATURDAY IS LOOKING TO BE THE FIRST DAY WITHOUT WIDESPREAD FOG. THAT
SAID, MID AND HIGH LEVEL CLOUDS LOOK TO REMAIN IN PLACE SO SKIES
WILL REMAIN PARTLY TO MOSTLY CLOUDY. HOWEVER, WITH WEAK WARM AIR
ADVECTION (WAA) IN PLACE, HIGH TEMPERATURES WILL WARM TO THE 40S AND
50S. WHILE THE DAY TIME HOURS WILL BE DRY, A STRONG COLD FRONT WILL
PUSH THROUGH THE AREA DURING THE EVENING TO OVERNIGHT TIMEFRAME. A
STRONG SHOT OF CAA WILL BE DELIVERED IN THE WAKE OF THIS FRONT WHILE
WINDS STRENGTHEN OUT OF THE NORTHWEST. GUSTS LOOK TO BE ON THE
STRONGER SIDE, REACHING UP TO ABOUT 30-40 MPH. AT THE SAME TIME,
CHANCES FOR PRECIPITATION LOOK TO RETURN VIA THE ELEVATED FRONT.
HOWEVER, PRECIPITATION LOOKS TO BEGIN FALLING SUNDAY MORNING. WITH
THE FRONT THROUGH THE AREA BY THEN, LOW TEMPERATURES WILL FALL TO
THE TEENS TO LOW 20S OVERNIGHT.
MIXED PRECIPITATION IS POSSIBLE THOUGH IT APPEARS TO BE MOST LIKELY
ACROSS PARTS OF NORTHWEST IOWA WHERE THERMAL PROFILES WILL BE A BIT
WARMER TO START OUT SUNDAY MORNING. DESPITE A DRY WEDGE OF AIR
BETWEEN ABOUT 850MB TO 650MB, THINK THE FORCING WILL BE STRONG
ENOUGH TO SATURATE THROUGH THIS LAYER. ONCE PROFILES ARE SATURATED,
PRECIPITATION WILL BE PRIMARILY SNOW WITH MINOR ACCUMULATIONS
POSSIBLE. CURRENTLY THINK THAT ACCUMULATIONS WILL BE LIGHT WITH MOST
SEEING BELOW AN INCH OF SNOW. THE ENSEMBLE SUPPORT THIS AS THEY ONLY
SHOW A 20-60% CHANCE FOR EXCEEDING AN INCH OF SNOW. THE GFS ENSEMBLE
HAS THE HIGHEST PROBABILITIES OUT OF ALL THE ENSEMBLES. THE POST
FRONTAL COLD ADVECTIVE REGIME WILL PERSIST FOR THE REST OF THE DAY,
CONTINUING STRONGER NORTHWEST WINDS WITH GUSTS SLIGHTLY
STRENGTHENING TO 30-45 MPH ACROSS THE AREA. HIGH TEMPERATURES WILL
BE MUCH COLDER, WITH HIGHS ONLY WARMING TO THE 20S TO ABOUT
FREEZING. WINDS WILL BE WEAKENING THROUGH SUNDAY NIGHT BUT LOWS WILL
BE MUCH COLDER, FALLING ALL THE WAY DOWN TO THE SINGLE DIGITS. WITH
BREEZY WINDS IN PLACE, WIND CHILLS WILL FALL TO ABOUT -5F TO -15F
ACROSS THE AREA.
MONDAY WILL BE THE COLDEST DAY OF THE WEEK WITH HIGHS ONLY WARMING
TO THE TEENS AND 20S. TEMPERATURES WILL SLOWLY START MODERATING TO
NEAR SEASONABLE BEGINNING ON TUESDAY AS WEAK WAA STRENGTHENS ALOFT.
BROAD NORTHWEST FLOW WILL TAKE OVER ALOFT. THIS WILL KEEP DRY
CONDITIONS FOR THE WEEK ALONG WITH NEAR SEASONABLE HIGH TEMPERATURES
IN THE 20S AND 30S. TUESDAY WILL BE THE WARMEST DAY WITH HIGHS
WARMING TO THE 30S AND 40S. LOW TEMPERATURES WILL ALSO BE NEAR
SEASONABLE IN THE SINGLE DIGITS AND TEENS.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1038 PM CST THU DEC 25 2025
IFR TO LIFR STRATUS AND FOG CONTINUE FOR NEARLY THE ENTIRE AREA
THROUGH AT EAST FRIDAY MORNING. GUIDANCE CONTINUES TO TREND
SLOWER WITH ANY IMPROVEMENT, SO MAY SEE THIS LINGER INTO THE
EARLY TO MID AFTERNOON HOURS. CONFIDENCE IS LOW ON THE TIMING
AND DURATION OF A RETURN TO MVFR OR VFR CONDITIONS FRIDAY. FOG
LOOKS TO DEVELOP AGAIN TOWARD THE END OF THE PERIOD ALONG AND
EAST OF I-29.
WINDS BECOME LIGHT AND REMAIN SO THROUGH FRIDAY EVENING.
DIRECTION WILL BE VARIABLE, TURNING NORTHWESTERLY TONIGHT AND
FRIDAY MORNING BEFORE SWITCHING TO SOUTHERLY TO END THE PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR SDZ038>040-
053>056-059>062-065>067-069>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 NEZ013-014.
DISCUSSION...MEYERS
AVIATION...SG
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page