938
FXUS63 KFSD 190939
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
339 AM CST THU FEB 19 2026
KEY MESSAGES
- A SIGNIFICANT SOUTHWARD SHIFT OCCURRED OVERNIGHT FOR TODAY'S
SNOWFALL, WITH THE MOST LIKELY OUTCOME KEEPING SNOW TOTALS
AROUND 2 INCHES OR LESS ALONG/SOUTH OF A LINE FROM SIOUX CITY
TO STORM LAKE.
- THERE IS STILL A LOW CHANCE (10-30%) FOR AMOUNTS REACHING OR
EXCEEDING 4 INCHES FROM SIOUX CITY TO STORM LAKE, AND THUS A
WINTER WEATHER ADVISORY REMAINS IN EFFECT IN THESE AREAS THIS
AFTERNOON/EVENING. IF THIS HIGHER END SCENARIO MATERIALIZES,
THE EVENING COMMUTE COULD BE IMPACTED BY RAPIDLY ACCUMULATING
SNOWFALL.
- DRY CONDITIONS ARE FAVORED FOR THE WEEKEND INTO EARLY NEXT
WEEK WITH TEMPERATURES REMAINING NEAR SEASONAL NORMALS THROUGH
MONDAY.
UPDATE
ISSUED AT 339 AM CST THU FEB 19 2026
HAVE LOWERED LOW TEMPERATURES SEVERAL DEGREES AS CLEAR SKIES AND
DECREASING WINDS HAVE ALLOWED READINGS TO FALL INTO THE TEENS,
EVEN IN THE ABSENCE OF FRESH SNOWFALL. HRRR SEEMS TO HAVE THE
BEST HANDLE ON THE COLDER TEMPERATURES AND WAS HEAVILY LEANED
UPON FOR TEMPERATURES THIS MORNING.
THE COLDER AND SOMEWHAT DRIER AIR IS ALSO REFLECTIVE OF THE LOW
LEVEL FRONT BEING PUSHED WELL SOUTH INTO KANSAS/NORTHERN MISSOURI,
WHICH WILL, IN PART, HAVE AN IMPACT ON SNOWFALL EVOLUTION THROUGH
TONIGHT. MUCH OF THIS WAS DISCUSSED IN OUR EVENING UPDATE, AND MADE
FURTHER ADJUSTMENTS TO QPF/SNOWFALL & HEADLINES IN RESPONSE TO THE
00Z MODEL TRENDS.
HOWEVER, THE 06Z RAP/HRRR GAVE US A LITTLE PAUSE IN JUMPING FULLY
INTO THE 00Z TREND, AS THOSE RUNS SHOW A SURGE OF MILDLY CONVECTIVE
SNOWFALL LIFTING NORTHWARD THROUGH WESTERN IOWA DURING THE VERY LATE
AFTERNOON/EARLY EVENING. THIS SURGE WOULD BRING A POTENTIAL FOR RAPID
SNOW ACCUMULATIONS DURING PORTIONS OF THE EVENING COMMUTE IN AREAS
FROM AROUND SIOUX CITY, NORTHEAST TOWARD CHEROKEE AND STORM LAKE
BEFORE PEELING OFF TO THE EAST. AS A RESULT, SNOWFALL PROBABILITIES
STILL SHOW A BROAD RANGE OF POTENTIAL TOTALS.
LOW END SCENARIO: DEEP DRY AIR WINS OUT AND MAINTAINS A VERY SHARP
NORTHERN GRADIENT TO THE SNOWBAND WHICH HAS SETTLED SOUTH OF THE
HIGHWAY 20 CORRIDOR IN MUCH OF THE 00Z GUIDANCE.
HIGH END SCENARIO: THE AFOREMENTIONED CONVECTIVE SURGE SEEN IN THE
06Z RAP/HRRR DOES INDEED SURGE NORTH, BRINGING HEAVY SNOWFALL RATES
(1 INCH/HOUR OR MORE) INTO THE SOUTHEAST COUNTIES OF OUR FORECAST
AREA, WHICH COULD RESULT IN A QUICK 3 TO 5 INCHES OF ACCUMULATION.
IN DEFERENCE TO THIS LOW PROBABILITY/HIGH END SCENARIO, MAINTAINED
THE WINTER WEATHER ADVISORY FOR DAKOTA COUNTY NEBRASKA, ALONG WITH
WOODBURY, IDA, CHEROKEE AND BUENA VISTA COUNTIES IN IOWA. CONTINUE
TO MONITOR THE LATEST FORECAST FOR UPDATES THROUGHOUT THE MORNING.
ISSUED AT 1050 PM CST WED FEB 18 2026
LATEST 18Z AND 00Z GUIDANCE HAS COME IN WITH A SIGNIFICANT SHIFT TO
THE SOUTH IN THE SNOW FOR TOMORROW. CURRENTLY LOOKS LIKE SNOW WILL
BEGIN DURING THE LATE MORNING TO EARLY AFTERNOON HOURS AND MAY HAVE
A CONVECTIVE COMPONENT TO IT. THE SNOW WILL EXPAND IN COVERAGE BUT
LOOKS TO STAY ALONG AND SOUTH OF HIGHWAY-20. IF SOME OF THE FURTHEST
SOUTH SOLUTIONS WERE TO VERIFY, THEN JUST ABOUT NO SNOW WOULD FALL
ANYWHERE IN THE AREA. THIS APPEARS TO BE DUE TO THE MODELS COMING
INTO BETTER CONSENSUS ON HOW THEY ARE HANDLING AN INTERNAL POTENTIAL
VORTICITY (PV) ANOMALY. THIS PV ANOMALY WILL SET UP A DEFORMATION
ZONE, STRENGTHENING THE FRONTAL FORCING AND ENHANCING SNOWFALL. BUT,
WITH THE MODELS HAVING A BETTER GRIP ON THIS PV ANOMALY, THE TRENDS
ARE TO PUSH THE BOUNDARY SOUTHWARDS. THERE REMAINS SOME INSTABILITY
ABOVE THE FRONTAL ZONE, INCREASING CONFIDENCE THAT THIS WILL BE A
TIGHT FRONTAL BAND. WITH THE BULK OF THE SNOW NOW FALLING GENERALLY
SOUTH OF THE AREA, HAVE TRIMMED A SIGNIFICANT PORTION OF THE
ADVISORY, NOW ONLY INCLUDING CLAY AND UNION COUNTIES IN SOUTH
DAKOTA, DIXON AND DAKOTA COUNTIES IN NEBRASKA, AND PLYMOUTH,
CHEROKEE, BUENA VISTA, WOODBURY, AND IDA COUNTIES IN NORTHWEST IOWA.
UP TO 3 INCHES OF SNOW IS POSSIBLE IN THE ADVISORY. HAVE ALSO
CHANGED THE TIMING OF THE ADVISORY, NOW KEEPING IT IN EFFECT FROM
NOON ON THURSDAY THROUGH MIDNIGHT. PATCHY BLOWING SNOW IS ALSO
POSSIBLE GIVEN THE BREEZY WINDS IN PLACE. WILL STILL WATCH TRENDS
THROUGH THE NIGHT AS ADDITIONAL SHIFTS BACK TO THE NORTH ARE
POSSIBLE.
DISCUSSION
ISSUED AT 305 PM CST WED FEB 18 2026
WINDS WILL CONTINUE TO SLOWLY DIMINISH THROUGH THE LATE AFTERNOON
AND EVENING, BUT OUTDOOR BURNING SHOULD CONTINUE TO BE AVOIDED AS
RELATIVE HUMIDITY VALUES ARE BELOW 25% ESPECIALLY NEAR
HIGHWAY-20 WHERE A CRITICAL FIRE DANGER REMAINS. THIS FIRE
DANGER WILL DIMINISH TONIGHT AS WINDS LIGHTEN AND RELATIVE
HUMIDITY VALUES RECOVER. TEMPERATURES DROP TO THE UPPER TEENS TO
LOW 20S TONIGHT, COLDEST OVER SOUTH-CENTRAL SOUTH DAKOTA AND
HIGHWAY-14 WHEREVER SNOW FELL TODAY. ATTENTION NOW TURNS TO OUR
NEXT STORM SYSTEM, WHICH IS DISCUSSED BELOW.
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL PLAINS THROUGH
THE DAY TOMORROW AND THEN PIVOT NORTHEASTWARDS TOWARDS THE GREAT
LAKES TOMORROW NIGHT. SNOW ASSOCIATED WITH THIS SYSTEM WILL MOVE
INTO SOUTH-CENTRAL SOUTH DAKOTA AROUND DAYBREAK AND CONTINUE PUSHING
EASTWARD THROUGH TOMORROW MORNING. THE SNOW WILL REACH THE
HIGHWAY-20 CORRIDOR IN FAR NORTHEAST NEBRASKA AND NORTHWEST
IOWA BY THE AFTERNOON AND CONTINUING LIFTING NORTHEASTWARD FROM
THERE. THE SNOW WILL GRADUALLY PULL AWAY TO OUR EAST THROUGH
TOMORROW NIGHT. IT'S CURRENTLY LOOKING LIKE THE GREATEST
SNOWFALL TOTALS WILL BE ALONG THE MISSOURI RIVER VALLEY INTO
NORTHWEST IOWA, WHERE A BROAD 2-5 INCHES OF SNOW CAN BE
EXPECTED. THIS WAS ENOUGH TO WARRANT ISSUING A WINTER WEATHER
ADVISORY STARTING AT 6 AM TOMORROW FOR AREAS WEST OF THE SIOUX
CITY METRO AND THEN STARTING AT NOON ALONG AND EAST OF THERE.
GUIDANCE CONTINUES TO SUGGEST THAT A NARROW BAND OF HEAVIER SNOW
WILL LIKELY DEVELOP EITHER OVER PARTS OF THE AREA OR JUST SOUTH
AND EAST OF US. THE LOCATION OF THIS BAND IS WHERE THE GREATEST
UNCERTAINTY LIES WITH THIS FORECAST, BUT IF IT DOES SET-UP OVER
OUR AREA, THEN A NARROW STRIPE OF 5-7+" WILL CERTAINLY BE
POSSIBLE. THE AREA TO WATCH FOR THESE HIGHER TOTALS WILL BE FROM ROUGHLY
ALONG AND SOUTH OF A SIOUX CITY TO SPENCER LINE. IF CERTAINTY
GROWS AS TO WHERE THIS NARROWER BAND SETS UP, THEN UPGRADES TO
WINTER STORM WARNINGS WILL BE POSSIBLE. EITHER WAY, BREEZY
CONDITIONS WHEN EVEN LIGHT SNOW IS FALLING WILL REDUCE
VISIBILITY TO LESS THAN ONE MILE AT TIMES, SO BE SURE TO USE
EXTRA CAUTION ON THE ROADS. WINDS DON'T LOOK TO BE AS STRONG AS
WHAT WE'VE SEEN TODAY, BUT COULD STILL GUST AS HIGH AS 40 MPH IN
SOUTH-CENTRAL SOUTH DAKOTA. WINDS WILL BE A BIT LIGHTER FARTHER
EAST, GUSTING UP TO 30 MPH ALONG AND EAST OF I-29. THIS WILL
MEAN THE STRONGEST WINDS WILL BE OFFSET FROM THE HEAVIEST SNOW
POTENTIAL TOMORROW AFTERNOON/EVENING, BUT TRENDS WILL BE
MONITORED CLOSELY BECAUSE IF WINDS LOOK TO BE A BIT STRONGER
OVER NORTHWEST IOWA THAN CURRENTLY EXPECTED, THEN BRIEF NEAR-
WHITEOUT TO WHITEOUT CONDITIONS WILL BE POSSIBLE. SNOWFALL
TOTALS WILL DECREASE QUICKLY WITH NORTHERN EXTENT AS DRY AIR
TRIES TO WRAP AROUND THE NORTH-SIDE OF THE SYSTEM AND FRONTAL
FORCING BECOMES WEAKER. THIS WILL LEAD TO SNOWFALL AMOUNTS AS
FAR NORTH AS THE I-90 CORRIDOR TO BE GENERALLY LESS THAN INCH,
EXCEPT FOR THOSE AREAS ALONG I-90 THAT ARE ALSO EAST OF
HIGHWAY-75 IN SOUTHWEST MINNESOTA WHERE UP TO 2 INCHES ARE
POSSIBLE.
COLDER TEMPERATURES SETTLE IN THIS WEEKEND, WITH HIGHS IN THE 20S
AND 30S FRIDAY THROUGH SUNDAY AND MORNING LOWS RETURNING TO THE
SINGLE DIGITS BY SATURDAY MORNING. QUIET WEATHER LOOKS LIKELY
INTO EARLY NEXT WEEK, WITH OUR NEXT SYSTEM TO DEAL WITH LIKELY
NOT MOVING IN UNTIL MID-WEEK, THOUGH CONFIDENCE IS LOW ON
DETAILS WITH THIS.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1050 PM CST WED FEB 18 2026
MAINLY VFR CONDITIONS BEGIN THE TAF PERIOD. SOME MVFR STRATUS
PERSISTS ALONG PORTIONS OF HIGHWAY-14 LATE THIS EVENING. THOUGH
LATEST TRENDS ARE SHOWING THIS STRATUS PUSHING TOWARDS KFSD. HAVE
DECIDED TO AMENED KFSD'S TAF TO INCLUDE MENTION OF THIS INCOMING
STRATUS. TRENDS IN THIS MVFR STRATUS WILL BE MONITORED THROUGH THE
NIGHT. MARGINALLY BREEZY WINDS ARE EXPECTED TO PERSIST THROUGH THE
OVERNIGHT HOURS WHILE TURNING NORTHERLY. MORE EXPANSIVE LOW LEVEL
STRATUS WILL DEVELOP BY TOMORROW MORNING. THIS STRATUS IS EXPECTED
TO SIT AT PREDOMINATELY MVFR LEVELS WITH POCKETS OF IFR POSSIBLE.
SOME SNOW REMAINS POSSIBLE FOR MAINLY HIGHWAY-20 TOMORROW AFTERNOON.
HAVE KEPT PROB30 GROUPS IN KSUX'S TAF BUT LATEST TRENDS KEEP THE
SNOW GENERALLY SOUTH OF KSUX. WILL KEEP AN EYE ON TRENDS IN THE SNOW
THROUGH THE NIGHT AS ADDITIONAL SHIFTS IN THE TRACK OF THE SNOW
REMAIN POSSIBLE.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST
TONIGHT FOR IAZ021-022-031-032.
NE...WINTER WEATHER ADVISORY FROM NOON TODAY TO MIDNIGHT CST
TONIGHT FOR NEZ014.
UPDATE...MEYERS
DISCUSSION...SAMET
AVIATION...JH/MEYERS
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