442
FXUS63 KFSD 210812
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
312 AM CDT SAT MAR 21 2026
KEY MESSAGES
- VERY ISOLATED FOG IS POSSIBLE THROUGH MID THIS MORNING ACROSS
RIVER VALLEYS AND OTHER LOW LYING AREAS.
- NEAR RECORD TO RECORD TEMPERATURES EXPECTED TODAY.
- ELEVATED TO CRITICAL FIRE DANGER THIS AFTERNOON AND EVENING
ALONG THE MISSOURI RIVER VALLEY INTO NORTHWESTERN IOWA. USE
CAUTION TO PREVENT FIRE START, AND REPORT FIRES TO LOCAL
AUTHORITIES.
- STRONG NORTHWESTERLY WINDS EXPECTED TONIGHT INTO EARLY SUNDAY
BEHIND A COLD FRONT. GUSTS NEAR TO ABOVE 40 MPH ALONG WITH
MUCH COLDER - BUT NEAR NORMAL - TEMPERATURES EXPECTED. LITTLE
TO NO PRECIPITATION ANTICIPATED.
- A ROLLER COASTER RIDE OF TEMPERATURES AND WIND IS EXPECTED
NEXT WEEK, INCREASING FIRE DANGER, BUT WITH LITTLE TO NO RAIN
ANTICIPATED.
UPDATE
ISSUED AT 249 AM CDT SAT MAR 21 2026
WINDS OVERNIGHT REMAIN FAIRLY LIGHT AND VARIABLE AND WITH CLEARING
SKIES, TEMPERATURES ARE FALLING INTO THE 40S. MAY SEE SOME ISOLATED
VALLEY FOG THROUGH THE MID MORNING HOURS AS ANY LOW LEVEL MOISTURE
REMAINS TRAPPED UNDER A STRONG INVERSION.
MAIN FOCUS REMAINS ON THE NEAR TO RECORD BREAKING HEAT AND RESULTANT
FIRE WEATHER CONCERNS (MORE DETAILS ON THAT IN THE FIRE WEATHER
SECTION BELOW). CONTINUED VERY WARM 925MB AND 850MB TEMPERATURES
OVER THE REGION AS WELL AS SOUTHWESTERLY FLOW SKYROCKETS HIGH
TEMPERATURES TODAY INTO THE 80S ACROSS THE REGION, WITH SOME
LOCATIONS REACHING THE LOWER 90S IN THE SOUTHERN MO RIVER VALLEY.
MORE DETAILS REGARDING THE CLIMATOLOGY OF THIS EXTREME WARMTH CAN BE
FOUND IN THE CLIMATE SECTION.
A COLD FRONT SWEEPS SOUTH TONIGHT. EXPECT BREEZY NORTHWESTERLY WINDS
BEHIND THE COLD FRONT LATE THIS EVENING THROUGH THE OVERNIGHT HOURS
AS CAA INCREASES. WIDESPREAD GUSTS OF UP TO 40 MPH AREA EXPECTED
LATE TONIGHT INTO THE OVERNIGHT HOURS, WITH POCKETS OF GUSTS 45 MPH
OR HIGHER. THESE STRONGER GUSTS MAY ONLY LAST AN HOUR OR TWO AT ANY
LOCATION. NBM PROBABILITIES OF EXCEEDING 45 MPH ARE LOW (LESS THAN
25%) AND FOCUSED WEST OF I-29, WITH ENSEMBLE PROBABILITY AROUND THE
SAME VALUES FOR EXCEEDING 40 MPH. THAT SAID, CAMS CONTINUE TO BE
PRETTY BULLISH WITH SOME OF THESE HIGHER GUSTS, SO WOULD NOT BE
SURPRISED IF THINGS TREND BACK A BIT STRONGER AND/OR A WIND ADVISORY
IS NEEDED IN THE NEXT 24 HOURS. AS FOR PRECIPITATION, AN ISOLATED
SHOWER IS POSSIBLE TONIGHT/EARLY SUNDAY NORTH OF I-90, BUT MOST OF
THE AREA CONTINUES TO STRUGGLE WITH SATURATION. COOLER BUT BREEZY ON
SUNDAY.
DISCUSSION
ISSUED AT 1214 PM CDT FRI MAR 20 2026
THIS AFTERNOON: YET ANOTHER SPECTACULAR MID-MARCH AFTERNOON ACROSS
THE TRI-STATE AREA AS TEMPERATURES CONTINUE TO RISE THROUGH THE 60S
AND INTO THE 70S. A FEW 80S WILL ALSO BE POSSIBLE ALONG THE MO RIVER
VALLEY. WHILE RH VALUES ARE FALLING INTO TO 20% RANGE SOUTH OF I-90
THIS AFTERNOON, WINDS REMAIN BELOW RFW CRITERIA.
TONIGHT: THE PASSAGES OF MID-LVL VORTICITY WILL CLEAR OUT CIRRUS
OVERNIGHT TONIGHT, WITH LIGHT AND VARIABLE WINDS DEVELOPING THROUGH
THE EVENING. THESE WINDS WILL BECOME MORE SOUTHERLY OR
SOUTHWESTERLY THROUGH THE NIGHT, ALLOWING THE DIURNAL
TEMPERATURES FALL TO STABILITY OR EVEN RISE INTO DAYBREAK
SATURDAY.
SATURDAY: A NEAR RECORD TO RECORD DAY IS EXPECTED THROUGH THE
REGION ON SATURDAY AS TEMPERATURES ARE EXPECTED TO SOAR INTO THE
UPPER 70S AND 80S IN THE AFTERNOON. A FEW LOCATIONS ALONG THE
MISSOURI RIVER VALLEY MAY REACH THE 90 DEGREE MARK. A VERY DRY DAY
IS EXPECTED SATURDAY, INCREASING FIRE WEATHER CONCERNS IN THE
AFTERNOON. THE GREATEST RISKS ARE LIKELY FOUND ALONG OR MOSTLY SOUTH
OF THE MISSOURI RIVER VALLEY AND HIGHWAY 20. PLEASE SEE SEPARATE
FIRE WEATHER DISCUSSION FOR MORE DETAILS.
SATURDAY NIGHT: GUIDANCE REMAINS CONSISTENT BRINGING A STRONG COLD
FRONT SOUTHWARD SATURDAY EVENING AND TRACKING SOUTH THROUGH THE
NIGHT. THIS FRONT ENTERS THE HIGHWAY 14 CORRIDOR AROUND 00Z, ENTERS
AREAS SOUTH OF I-90 BY 10PM, AND CLEARS THE CWA BY 1AM. LATEST
GUIDANCE CONTINUES TO SHOW A TIGHT SPG DEVELOPING BEHIND THE FRONT,
SUGGESTING SUSTAINED WINDS OF 20+ MPH ARE POSSIBLE. THE STRONG COLD
ADVECTION BEHIND THE BOUNDARY WILL CREATE A STEEP LOW-LVL LAPSE RATE
INTO SUNDAY MORNING, SUGGESTING AN INCREASED POSSIBILITY FOR 35 TO
45 MPH GUSTS INTO DAYBREAK. GIVEN THE NBM LOW BIAS IN THESE SETUPS,
HAVE BLENDED IN MORE 90TH PERCENTILE AND HIGH RESOLUTION CAM
WINDS.
SUNDAY: COLD ADVECTION PERSISTS THROUGH SUNDAY, WITH WITH A RATHER
BREEZY SUSTAINED WIND THROUGH THE DAY. AFTER REACHING THE 80S
SATURDAY AFTERNOON, DAYBREAK WIND CHILLS IN PORTIONS OF THE CWA WILL
BE NEARLY 60 DEGREES COLDER. TEMPERATURES IN THE AFTERNOON WILL
REBOUND BACK TO THE UPPER 40S TO LOWER 50S IN MOST LOCATIONS. LATEST
ENSEMBLE GUIDANCE CONTINUES TO BACK OFF ON THE POTENTIAL FOR
MEASURABLE RAINFALL SUNDAY MORNING, THOUGH THE PRESENCE OF LOWER
STRATUS COULD STILL RESULT IN SPRINKLES NORTH OF I-90.
MONDAY-WEDNESDAY: THE FORECAST REMAINS ON TRACK FOR THE FIRST HALF
OF NEXT WEEK AS QUASI-ZONAL FLOW TO AN AMPLIFIED RIDGE PATTERN
DEVELOPS. INITIAL COLD AIR MASS THAT ADVECTS SOUTHWARD SUNDAY WILL
QUICKLY BECOME SHUNTED EASTWARD AS LEE-SIDE TROUGHING REDEVELOPS
OVER THE WESTERN PLAINS. LOW-LVL THERMAL ADVECTION WILL
INCREASE FIRST OVER CENTRAL SOUTH DAKOTA, ALIGNED WITH AN
INCREASED SPG. THERE REMAIN SOME HINTS AT LOW-LVL MOISTURE
TRANSPORT INTO THE DAKOTAS EARLY MONDAY WHICH COULD RESULT IN
ISOLATED TO SCATTERED SHOWERS. FURTHER EAST, INCREASING SURFACE
WINDS WILL BEGIN TO HEIGHTEN FIRE DANGER RISKS BY MID-LATE
AFTERNOON.
TEMPERATURES WARM FURTHER TUESDAY AND WEDNESDAY AS THE ORIENTATION
OF LOW-LVL WARM ADVECTION SPREAD EASTWARD AND OVER THE TRI-STATE
AREA. WE'LL AGAIN SEE TEMPERATURES CLIMB INTO TO 60S AND THEN 70S
BY WEDNESDAY. ONE THING THAT WE'LL NEED TO KEEP A CLOSE EYE ON IS
THE MIXDOWN OF DRY AIR EACH AFTERNOON. GIVEN THE PERSISTENT
SOUTHERLY TO SOUTHWESTERLY SURFACE FLOW OFF THE DRIER CENTRAL
PLAINS, WE COULD SEE SIGNIFICANTLY LOWER DEWPOINTS DEVELOP THAN WHAT
THE DETERMINISTIC NBM SUGGESTS. THE FULL RANGE OF NBM GUIDANCE WOULD
SUGGEST A NEARLY 10-15 DEGREE SPREAD IN THE 25/75TH PERCENTILE
DEW POINT VALUES EACH AFTERNOON. THIS DIFFERENCE REPRESENTS THE
POTENTIAL FOR 20-25% RH VS THE CURRENTLY FORECAST 35% RH VALUES
AND WHEN COMBINED WITH AFTERNOON GUSTS APPROACHING 25+ MPH
COULD RESULT IN HIGHER FIRE WEATHER CONCERNS BOTH DAYS.
THURSDAY-FRIDAY: WE'LL FINISH THE WORK WEEK WITH ANOTHER STRONG COLD
FRONT PLUNGING SOUTHWARD BY THURSDAY. BEHIND THIS FRONT, ANOTHER
ROUND OF GUSTY NORTHWEST WINDS ARE LIKELY, WITH HIGHS FALLING BACK
TO THE 40S BY FRIDAY. THE EXPECTATION GIVEN AGREEMENT IN ENSEMBLE
DATA IS THAT LITTLE TO NO IMPACTFUL PRECIPITATION IS EXPECTED
THROUGH NEXT WEEK. LONG RANGE LREF GUIDANCE THROUGH NEXT
SATURDAY ONLY SUGGESTS A 10-20% PROBABILITY FOR MORE THAN 0.10"
OF QPF OVER THE 7 DAY FORECAST, WITH A 0-5% PROBABILITY OF MORE
THAN 0.25" AT ANY ONE POINT.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1226 AM CDT SAT MAR 21 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL THIS PERIOD. CLOUDS SLOWLY
PUSH SOUTHEAST THROUGH THE OVERNIGHT BECOMING CLEAR. EARLY MORNING
PATCHY FOG IS POSSIBLE, MOSTLY ALONG LOW LAYING AREAS AND RIVER
VALLEYS. LIGHT AND VARIABLE WINDS BECOME SOUTHERLY TO SOUTHWESTERLY.
GUST OF 15-22 KTS ARE EXPECTED FOR AREAS AT ELEVATION IN SOUTH
CENTRAL SOUTH DAKOTA AND ALONG THE BUFFALO RIDGE IN SOUTHWEST
MINNESOTA. WINDS DECREASE BRIEFLY IN THE EVENING BEFORE THE APPROACH
OF A SURFACE LOW PRESSURE AND COLD FRONT TURN WINDS TO THE NORTH.
WINDS RAPIDLY INCREASE BEHIND THE FRONT BEGINNING ALONG HIGHWAY 14
IN THE EARLY EVENING SATURDAY, AND PUSH SOUTH THROUGH THE END OF THE
PERIOD. GUSTS OF 25-30 KTS ARE EXPECTED EAST OF I-29. TO THE
WEST GUSTS OF 30-35 KT GUSTS ARE EXPECTED, WITH THE HIGHEST
GUSTS LOCATED OVER SOUTH CENTRAL SOUTH DAKOTA.
FIRE WEATHER
ISSUED AT 312 AM CDT SAT MAR 21 2026
RED FLAG WARNING IS IN EFFECT FOR THE MISSOURI RIVER VALLEY AND INTO
NORTHWESTERN IA THIS AFTERNOON AND THROUGH THE EVENING HOURS.
TEMPERATURES WARM INTO THE 80S TO NEAR 90, AND WITH VERY LOW DEW
POINTS, HUMIDITY VALUES FALL TO AROUND 12%. CRITICAL CONDITIONS MAY
ONLY BE MET OR CLOSE TO BEING MET FOR A COUPLE OF HOURS THIS
AFTERNOON INTO THIS EVENING; HOWEVER, VERY LOW HUMIDITY AND DRY
FUELS MAY BE ENOUGH TO OVERCOME THE LESS THAN CRITICAL SOUTHWESTERLY
WINDS. ELEVATED TO NEAR CRITICAL CONDITIONS WILL STRETCH FURTHER
NORTH TO THE I-90 CORRIDOR, BUT MORE RECENT SNOW MELT AND SLIGHTLY
HIGHER RH (NEAR 20%) MAY LIMIT CONCERNS. THAT SAID, EXPANSION OF THE
RED FLAG WARNING COULD BE WARRANTED IF WINDS EXCEED CURRENT
EXPECTATIONS.
WINDS WILL BRIEFLY LULL AHEAD OF A COLD FRONT SWEEPING SOUTH
TONIGHT, BEFORE TURNING NORTHWESTERLY AND INCREASING AFTER 10 PM.
WIND GUSTS TONIGHT INTO THE OVERNIGHT HOURS LOOK TO BE AROUND 40
MPH, STRONGEST WINDS FOR A COUPLE OF HOURS. GUSTS MAY APPROACH OR
EXCEED 45 MPH.
COOLER TEMPERATURES AND INCREASED HUMIDITY ARE EXPECTED INTO EARLY
NEXT WEEK, BUT DRY AND BREEZY CONDITIONS MAY LEAD TO ELEVATED FIRE
DANGER. WARMER TEMPERATURES RETURN BY MID WEEK WITH LITTLE TO NO
PRECIPITATION.
CLIMATE
ISSUED AT 1253 PM CDT THU MAR 19 2026
EXTREMELY WARM AIR WILL TRY TO MOVE EASTWARD LATE THIS WEEK INTO
THIS WEEKEND. THESE TEMPERATURES MAY RESULT IN THE TOP 10
EARLIEST 75 AND 80 DEGREE HIGHS AT LONG TERM CLIMATE LOCATIONS.
HERE IS A LOOK AT RECORDS FOR FRIDAY AND SATURDAY
RECORD HIGH TEMPERATURES:
MARCH 20:
KFSD: 73/2022, KSUX: 79/2015, KHON: 75/1911, KMHE: 77/1994
MARCH 21:
KFSD: 83/1910, KSUX: 85/1910, KHON: 84/1907, KMHE: 88/1907
RECORD HIGH MINIMUM TEMPERATURES:
MARCH 21:
KFSD: 49/1938, KSUX: 48/2012, KHON: 45/1938
FSD WATCHES/WARNINGS/ADVISORIES
SD...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR SDZ050-063-068>071.
MN...NONE.
IA...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR IAZ020-031-032.
NE...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR NEZ013-014.
UPDATE...SG
DISCUSSION...DUX
AVIATION...AJP
FIRE WEATHER...SG
CLIMATE...DUX
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