391
FXUS63 KFSD 252327
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
527 PM CST THU DEC 25 2025
KEY MESSAGES
- DENSE FOG WITH VISIBILITY 1/2 MILE OR LESS IS EXPECTED TO
ONLY SLOWLY IMPROVE THROUGH THE NIGHT AND THE DENSE FOG MAY
LINGER INTO FRIDAY MORNING WITH THE HIGHEST CHANCE FOR THIS
OCCURRING NEAR AND EAST OF I-29.
- 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-EARLY
MONDAY.
- AREAS OF LIGHT SNOW OR FLURRIES COULD ACCOMPANY THE COLDER
AIR ON SUNDAY. LIGHT SNOW ACCUMULATIONS ARE POSSIBLE, WITH
AREAS OF BLOWING SNOW IF ACCUMULATIONS APPROACH AN INCH OR
MORE.
DISCUSSION
ISSUED AT 211 PM CST THU DEC 25 2025
A QUICK MOVING WAVE WILL BRING VERY SPOTTY, LIGHT PRECIPITATION THIS
AFTERNOON INTO TONIGHT WITH LITTLE TO NO IMPACTS, BUT THIS WAVE WILL
SWING THROUGH A WEAK COLD FRONT. THE LATEST MODEL SOUNDINGS ARE
PRETTY PESSIMISTIC ABOUT SCOURING OUT THE STRATUS AND FOG WITH THIS
BOUNDARY, SO WENT AHEAD AND EXTENDED THE DENSE FOG ADVISORY THROUGH
FRIDAY MORNING FOR MOST LOCATIONS EAST OF THE JAMES RIVER. AREAS
NEAR AND EVEN WEST OF THE JAMES RIVER MAY NEED TO BE INCLUDED IN
THIS ADVISORY IF CONFIDENCE IN CREASES AS THE DRY PUNCH WITH THIS
BOUNDARY IS NOT EXPECTED TO BE VERY STRONG. WINDS WILL QUICKLY TURN
BACK TO THE SOUTH ON FRIDAY AFTERNOON, ALBEIT NOT VERY STRONGLY.
THIS WILL LEAD TO A MILD WINTER DAY, LIKELY STILL FIGHTING SOME
STRATUS AND FOG CONCERNS.
FRIDAY NIGHT INTO SATURDAY SHOWS POTENTIAL TO BE VERY MILD, HOWEVER
TEMPERATURES ALOFT WARM A DECENT AMOUNT FRIDAY NIGHT AND WE COULD
SEE SOME FOG AND STRATUS CHALLENGES AGAIN, WHICH OF COURSE IF THEY
LINGER INTO THE DAY SATURDAY WOULD LIMIT ANY DAYTIME RISE IN
TEMPERATURES. FOR NOW THINKING 50S IN MANY LOCATIONS, WITH THE
BETTER CHANCES NEAR THE MISSOURI RIVER.
A STRONGER WAVE DIGS INTO THE AREA SATURDAY NIGHT INTO SUNDAY AND IF
THERE IS ANY FOG AND STRATUS LEFT, IT WILL ERODE QUICKLY THROUGH
SUNDAY MORNING AS COLDER AND DRIER AIR BUILDS SOUTH. THERE WILL BE A
CHANCE FOR SOME LIGHT SNOW SUNDAY BUT SOME OF THE MODEL SOUNDINGS
INDICATING A BIT OF A DRY WEDGE FROM AROUND 900MB TO 700MB WHICH
WOULD LIMIT PRECIPITATION PRODUCTION AT THE SURFACE SO FOR NOW ONLY
A VERY LOW CHANCE FOR IMPACTFUL SNOWFALL ON SUNDAY. THE LATEST GEFS
AND EC AI BRINGING ABOUT A 20-30 PERCENT CHANCE FOR AN INCH OF SNOW
WHILE THE EC ENSEMBLE IS LESS THAN 10 PERCENT.
COLD HIGH PRESSURE BUILDS SOUTH SUNDAY NIGHT INTO MONDAY BRING BELOW
NORMAL TEMPERATURES FOR BOTH SUNDAY AND MONDAY. WITHOUT MUCH SNOW
LEFT ON THE GROUND TEMPERATURES WILL BE LIMITED ON HOW COLD THEY
WILL GET.
TUESDAY INTO THURSDAY APPEARS TO KEEP MAINLY DRY CONDITIONS IN PLACE
WITH STRONG NORTHWEST FLOW ALOFT. TEMPERATURES TUESDAY LIKELY TO BE
ABOVE NORMAL, THEN COOLER AIR MAY SETTLE SOUTH AND DROP TEMPERATURES
BELOW NORMAL, BUT CONFIDENCE ON THIS IS A BIT LOW WITH SOME
DISAGREEMENT ON THE STRENGTH OF THE COLD AIR AS WELL AS THE
OCCASIONAL LOWER PREDICTABILITY OF THESE WEAKER WAVES IN NORTHWEST
FLOW.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 522 PM CST THU DEC 25 2025
IFR TO LIFR CONDITIONS PREVAIL THROUGH MUCH OF THE PERIOD FOR
MOST OF THE AREA WITH STUBBORN VERY LOW STRATUS AND FOG, LOCALLY
DENSE WITH VISIBILITY BELOW 1/4 SM AT TIMES. CAN'T RULE OUT
SOME SPRINKLES THIS EVENING WITH A BOUNDARY PUSHING THROUGH THE
AREA. WITH THE BOUNDARY PUSHING THROUGH, WIND DIRECTION WILL BE
QUITE VARIABLE THROUGH THE PERIOD.
BIGGEST QUESTIONS THROUGH THE TAF PERIOD WILL BE WHEN AND HOW
LOW CONDITIONS WEST OF THE JAMES RIVER DROP, WHERE WE'VE SEEN
SOME IMPROVEMENT IN STRATUS/VISIBILITY DURING THIS AFTERNOON.
THE OTHER QUESTION IS HOW QUICKLY FOG AND STRATUS LIFT DURING
THE MORNING HOURS FRIDAY, WITH MOST GUIDANCE KEEPING IFR TO LIFR
CEILINGS AROUND INTO THE AFTERNOON HOURS. DID LEAN A BIT MORE
PESSIMISTIC WITH IMPROVEMENTS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...DENSE FOG ADVISORY UNTIL 9 AM CST FRIDAY FOR SDZ039-040-055-
056-061-062-066-067-069>071.
MN...DENSE FOG ADVISORY UNTIL 9 AM CST FRIDAY FOR MNZ071-072-080-
081-089-090-097-098.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST FRIDAY FOR IAZ001>003-
012>014-020>022-031-032.
NE...DENSE FOG ADVISORY UNTIL 9 AM CST FRIDAY FOR NEZ013-014.
DISCUSSION...08
AVIATION...SG
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