526
FXUS63 KFSD 131118
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
518 AM CST THU NOV 13 2025
KEY MESSAGES
- PATCHY VALLEY FOG IS POSSIBLE THIS MORNING AND FRIDAY MORNING.
BE PREPARED FOR CHANGING CONDITIONS AND PATCHY SLICK SPOTS
WITH TEMPERATURES NEAR FREEZING FOR THE MORNING COMMUTE.
- ABOVE AVERAGE TEMPERATURES CONTINUE INTO THE WEEKEND, WITH THE
WARMEST CONDITIONS EXPECTED FRIDAY - APPROACHING RECORDS FOR
SOME LOCATIONS. TEMPERATURES MODERATE NEAR SEASONAL EARLY NEXT
WEEK.
- MOSTLY DRY CONDITIONS PERSIST INTO THE WEEKEND WITH OUR NEXT
PRECIPITATION CHANCES RETURNING EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 247 AM CST THU NOV 13 2025
THROUGH TONIGHT: THIS MORNING, WE'RE WATCHING SOME MID AND UPPER
CLOUDS MOVE ACROSS THE AREA. GUIDANCE HAS BACKED OFF A BIT ON THE
POTENTIAL FOR VALLEY FOG THIS MORNING. HOWEVER, WINDS HAVE GENERALLY
BEEN LIGHT TO CALM, AND WITH TEMPERATURES IN THE 30S, WOULD NOT BE
SURPRISED TO SOME PATCHY DEVELOPMENT.
ANOTHER MILD DAY WITH RIDGING BUILDING TO THE WEST. INCREASED HIGHS
FROM PREVIOUS BY A COUPLE OF DEGREES, GIVEN HOW WE'VE BEEN WARMING
MORE THAN EXPECTED THE LAST COUPLE DAYS AND WE REMAIN IN A WAA
REGIME. A MIX OF MID/HIGH CLOUDS AND SUNSHINE WITH HIGHS IN THE
UPPER 50S TO UPPER 60S.
FRIDAY: MORE OF THE SAME FOR FRIDAY. MAY AGAIN SEE SOME PATCHY
VALLEY FOG OVERNIGHT INTO THE MORNING, ALTHOUGH NAM GUIDANCE REMAINS
THE MOST BULLISH IN COVERAGE AND HOW LOW VISIBILITY DROPS.
OTHERWISE, WELL ABOVE AVERAGE TEMPERATURES EXPECTED. THIS IS DUE TO
INCREASED WAA AND SOUTHERLY LOW LEVEL FLOW AS WELL AS CONTINUED BUT
FLATTENING RIDGING ALOFT. BASED ON RECENT TRENDS, RAISED HIGHS FROM
THE NBM USING SOME OF THE NBM 75TH PERCENTILE. EXPECT HIGHS TOMORROW
IN THE MID 60S TO MID AND EVEN UPPER 70S. IF CURRENT FORECAST HOLDS,
WE WILL BE WITHIN 3 DEGREES OF RECORD AT ALL FOUR OF OUR CLIMATE
SITES: SIOUX FALLS AND MITCHELL (WITHIN 3 DEGREES) AND HURON AND
SIOUX CITY (TYING RECORD).
WINDS WILL BE BREEZY WITH A COMPRESSING SURFACE PRESSURE GRADIENT
AHEAD OF THE NEXT SURFACE BOUNDARY. SOUTHWESTERLY WINDS TOMORROW MAY
GUST AROUND 20-30 MPH. RECENT DRY CONDITIONS AND LOWER HUMIDITY
VALUES LEAD TO ELEVATED FIRE DANGER - ESPECIALLY ACROSS SOUTH
CENTRAL SD WHERE THERE HAS BEEN LESS RECENT PRECIPITATION. USE
CAUTION TO PREVENT FIRE START.
FRIDAY NIGHT-SUNDAY: SURFACE FRONT TRACKS THROUGH THE AREA FRIDAY
NIGHT, WITH MID/UPPER TROUGH MOVING THROUGH EARLY ON SATURDAY.
SHOULD STAY DRY DURING THIS TIME WITH THE BETTER FORCING OFF TO THE
NORTH. HOWEVER, SOME SHORTER TERM GUIDANCE INDICATES THAT SHOWERS
MAY SNEAK INTO THE US HWY 14 CORRIDOR. PROBABILITIES OF MEASURABLE
PRECIPITATION REMAIN LESS THAN 20% NEAR US HWY 14, WITH THE HIGHER
PROBABILITIES ACROSS NORTHERN SD. FRIDAY NIGHT REMAINS MILD AHEAD OF
THE FRONT, WITH LOWS IN THE 40S. DEPENDING ON HOW QUICKLY TEMPS FALL
TONIGHT (I.E. HOW COOL WE GET FRIDAY MORNING), WE MAY APPROACH A
RECORD WARM LOW FOR FRIDAY AT HURON.
THIS TROUGH DEEPENS OVER THE GREAT LAKES ON SATURDAY, AND CAA WITH
NORTHWESTERLY FLOW WILL COOL TEMPERATURES SLIGHTLY. LOOKING FURTHER
WEST, WE'LL SEE A QUICK MOVING MID/UPPER LEVEL RIDGE APPROACH DURING
THE SECOND HALF OF THE WEEKEND AS CLOSED LOW DEEPENS IN THE
SOUTHWEST. SURFACE HIGH PRESSURE MOVES THROUGH ON SUNDAY AS WELL.
THE WEEKEND WILL BE COOLER WITH CAA AND NORTHWESTERLY FLOW. HIGHS IN
THE 50S. LOWS SATURDAY NIGHT COOL BACK TO NEAR SEASONAL NORMALS, IN
THE MID TO UPPER 20S AND LOWER 30S.
MONDAY-THURSDAY: MORE ACTIVE PATTERN CONTINUES INTO THE EARLY AND
MIDDLE PART OF NEXT WEEK. PREVIOUSLY MENTIONED CLOSED LOW ACROSS THE
SOUTHWESTERN US TRACKS NORTHEAST MONDAY AND TUESDAY, WITH GUIDANCE
SHIFTING TO A BIT MORE OF AN OPEN WAVE AS IT DOES SO. 13.00Z STILL
SHOWS A FAIR AMOUNT OF DISAGREEMENT IN TIMING AND TRACK, BUT
CONTINUES THE GENERAL SLOWING TREND. THE GFS IS QUICKER BUT FURTHER
SOUTH, RUNNING THE LOW THROUGH NE/KS BY MONDAY EVENING. THE GFS IS
ALSO THE ONLY OF THE THREE DETERMINISTIC MODELS WHICH SPLITS THE LOW
AS IT MOVES INTO THE CENTRAL PLAINS. THE ECMWF IS IN THE MIDDLE
TIMING WISE, BUT THE FURTHEST NORTH WITH THE LOW INTO THE DAKOTAS.
FINALLY, THE CANADIAN IS THE SLOWEST, RUNNING ABOUT 6 HOURS BEHIND
THE GFS BUT KEEPS THE LOW TO OUR SOUTH. WITH THIS MUCH UNCERTAINTY,
CONFIDENCE IS LOW IN THE DETAILS PARTICULARLY WITH REGARDS TO
PRECIPITATION. THAT SAID, PROBABILITY OF MEASURABLE PRECIPITATION
(0.01" OR MORE) IS MODERATE TO HIGH (OVER 60%) ALTHOUGH LOCATION OF
HIGHEST PROBABILITY CONTINUES TO VARY BETWEEN THE ENSEMBLES. FOR A
TENTH OF AN INCH, LOW TO MODERATE PROBABILITIES EXIST (30-60%). P-
TYPE WILL BE HIGHLY DEPENDENT ON TRACK/TIMING, BUT COULD SEE SOME
ACCUMULATION DURING THIS TIME.
TOWARD MID WEEK, WE'LL SEE THE NEXT TROUGH DIG IN ACROSS THE
ROCKIES, WITH A COUPLE OF SHORT WAVES MOVING THROUGH AHEAD OF IT.
CONFIDENCE IN DETAILS REMAINS LOW, BUT ACTIVE PATTERN LOOKS TO
REMAIN IN PLACE TOWARD MID TO LATE NEXT WEEK.
TEMPERATURES EARLY INTO MID NEXT WEEK REMAIN NEAR TO JUST ABOVE
SEASONAL AVERAGES.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 513 AM CST THU NOV 13 2025
VFR CONDITIONS PREVAIL, OUTSIDE OF A COUPLE OF LOWER END PATCHY
FOG CHANCES THIS FORECAST PERIOD. WINDS REMAIN LIGHT FOR MOST OF
THE AREA, WITH ISOLATED GUSTS AROUND 15 KNOTS.
VERY PATCHY VALLEY FOG IS POSSIBLE THROUGH THE MID MORNING
HOURS, WHICH COULD LEAD TO SOME LOCALLY MVFR OR LOWER
VISIBILITY. HOWEVER, GUIDANCE HAS BEEN TRENDING DOWN IN THIS
POTENTIAL OVER THE LAST COUPLE HI- RES MODEL RUNS, SO REMOVED
MENTION FROM KFSD GIVEN LOWER CONFIDENCE. AN'T ENTIRELY RULE
OUT ADDITIONAL PATCHY VALLEY FOG FRIDAY MORNING, BUT AGAIN,
CONFIDENCE IS TOO LOW TO INCLUDE AT THIS TIME.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...SG
AVIATION...SG
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