810
FXUS63 KFSD 240233
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
933 PM CDT FRI OCT 23 2026
KEY MESSAGES
- BREEZY CONDITIONS CONTINUE TONIGHT: WIND GUSTS SLOWLY DROP
OVER THE NEXT FEW HOURS, EXCEPT OVER THE BUFFALO RIDGE WHERE
WINDS COULD GUST TO 30-35 MPH THROUGH TONIGHT. A SECOND PUSH
OF STRONGER WINDS ARRIVES IN SOUTH-CENTRAL SOUTH DAKOTA NEAR/JUST
AFTER SUNRISE. GUSTS WITH THIS WILL INCREASE TO 35-40 MPH FOR
A BRIEF PERIOD.
- COOLER WITH SCATTERED WEEKEND RAIN: A SLOW-MOVING FRONT WILL
BRING INCREASED CLOUDS AND OCCASIONAL RAIN THIS WEEKEND.
TEMPERATURES WILL BE NOTABLY COOLER (40S/50S) BY SUNDAY.
- SIGNIFICANT RAINFALL LIKELY MONDAY-TUESDAY: A LARGE MULTI-DAY
SYSTEM WILL BRING WIDESPREAD RAIN TO START THE NEW WORK WEEK.
CONFIDENCE IN AMOUNTS OVER 1" THROUGH TUESDAY MORNING REMAIN
HIGH.
- ACTIVE WEATHER CONTINUES: A SECOND FAST MOVING SYSTEM MAY
BRING RAIN CHANCES BACK BY TUESDAY NIGHT AND WEDNESDAY, WITH
TEMPERATURES NEAR SEASONAL NORMALS.
UPDATE
ISSUED AT 931 PM CDT FRI OCT 23 2026
A WARM AND BREEZY LATE OCTOBER EVENING CONTINUES ACROSS THE AREA.
WIND GUSTS WILL GRADUALLY DROP OFF OVER THE NEXT FEW HOURS, THOUGH
GUSTS WILL REMAIN CLOSER TO 30-35 MPH OVER THE HIGHER ELEVATIONS OF
THE BUFFALO RIDGE THROUGH THE REMAINDER OF THE NIGHT. A COLD FRONT
WILL MOVE INTO THE AREA TOWARDS DAYBREAK, AND SOME STRONGER COLD AIR
ADVECTION BEHIND THIS WILL BRING ANOTHER UPTICK IN WIND GUSTS IN
SOUTH-CENTRAL SOUTH DAKOTA NEAR AND JUST AFTER SUNRISE. WIND GUSTS
WITH THIS WILL BE 35-40 MPH FOR A BRIEF PERIOD, THOUGH COULD SEE ONE
OR TWO GUSTS UP TO 45 MPH.
A COUPLE OF OTHER THINGS TO NOTE ABOUT THIS COLD FRONT AND HOW IT
AFFECTS THE FORECAST TONIGHT: IT WILL BRING A QUICK DROP IN
TEMPERATURES NEAR AND WEST OF THE JAMES RIVER TOWARDS SUNRISE, WITH
TEMPERATURES FALLING TO THE LOW TO MIDDLE 50S FOR MORNING LOWS.
SECONDLY, THERE WILL BE SOME RAIN SHOWERS THAT DEVELOP OUT OF AHEAD
OF THE FRONT. SOME ELEVATED INSTABILITY WILL LEAD TO A FEW RUMBLES
OF THUNDER, BUT SEVERE WEATHER IS NOT EXPECTED. THIS INSTABILITY
WILL WANE THROUGH THE DAY, SO THUNDER CHANCES WILL DECREASE AS WE GO
THROUGH THE DAYTIME HOURS SATURDAY. HOWEVER, SHOWER CHANCES LOOK TO
CONTINUE AS MORE MOISTURE MOVES INTO THE AREA AND SATURATES THE
COLUMN.
THERE WILL BE SOME DRY AIR NUDGING INTO OUR NORTHWESTERN-MOST AREAS
DURING THE DAY SATURDAY, SO THIS WILL LEAD TO A RELATIVELY SHARP
GRADIENT OF WHERE THE RAIN STARTS AND ENDS DURING THE DAY SATURDAY.
THE BETTER CHANCES (30-60%) WILL BE MAINLY NEAR AND EAST OF A
BROOKINGS TO MITCHELL TO LAKE ANDES LINE, WITH THAT LINE NUDGING
EASTWARD INTO THE LATER AFTERNOON AND EVENING HOURS. THE
AFOREMENTIONED COLD FRONT WILL ALSO CAUSE THE HIGH TEMPERATURE TO BE
IN THE MORNING FOR A LARGE PART OF THE AREA. THE EXCEPTION WILL BE
EAST OF MN/IA HIGHWAY 60 WHERE THE COLD FRONT ARRIVES LAST, AND THIS
IS WHERE HIGHS WILL BE REACHED DURING THE USUAL MID-AFTERNOON TIME
FRAME. ADJUSTED HOURLY TEMPERATURES SLIGHTLY FOR SATURDAY USING THE
LATEST GUIDANCE, BUT NO MAJOR CHANGES IN THE OVERALL TEMPERATURE
TREND TO NOTE.
DISCUSSION
ISSUED AT 1218 PM CDT FRI OCT 23 2026
THIS AFTERNOON: WINDS CONTINUE TO INCREASE EARLY THIS AFTERNOON WITH
OBSERVED GUSTS BETWEEN 30 AND 45 MPH. TEMPERATURES CONTINUE TO WARM
INTO THE 70S, AND POTENTIAL FOR SOME HIGHS IN THE 80S REMAIN
POSSIBLE ALONG AND WEST OF THE JAMES RIVER VALLEY. HOWEVER, A
PERSISTENT MID-UPR CLOUD DECK MAY LIMIT THE CLIMB THIS AFTERNOON.
OUT IN WESTERN SOUTH DAKOTA, WE'RE BEGINNING TO SEE THE FIRST SIGNS
OF A FRONTAL BOUNDARY FORMING THAT WILL GRADUALLY MOVE EASTWARD
OVERNIGHT. THE FIRE DANGER REMAINS VERY HIGH THIS AFTERNOON,
ESPECIALLY FOR AGRICULTURAL AREAS, PLEASE SEE SEPARATE DISCUSSION.
TONIGHT: AN ELONGATED UPPER TROUGH STRETCHING ACROSS THE ROCKIES AND
INTO SOUTHERN CALIFORNIA WILL BEGIN TO STRETCH AND SPLIT IN TWO
OVERNIGHT. NORTHERN ENERGY TRACKING EASTWARD ACROSS SOUTHERN CANADA
WILL BE STRONG ENOUGH TO NUDGE THE AFOREMENTIONED SURFACE BOUNDARY
INTO THE I-29 CORRIDOR BY MID-MORNIGN SATURDAY. AHEAD OF THIS
BOUNDARY, CONVERGENCE ON A 40 KNOT LLJ AND THE ARRIVAL OF A MID-LVL
VORTICITY MAXIMA SHOULD BE ENOUGH TO ALLOW ISOLATED TO SCATTERED
SHOWERS TO DEVELOP AND AND AHEAD OF THIS BOUNDARY. MUCAPE MAY BE AS
HIGH AS 300 J/KG AFTER 3AM, SO HAVE INCREASED POTTHUNDER TO AT LEAST
SUGGEST ISOLATED LIGHTNING STRIKES INTO MID-MORNING.
SATURDAY-SUNDAY: WHILE NORTHERN STREAM ENERGY MOVES EASTWARD ACROSS
CANADA, A LARGE UPPER TROUGH WILL REMAIN OVER THE FOUR CORNERS
REGION THROUGH THE WEEKEND. OVERHEAD AND CLOSER TO HOME, THE
AFOREMENTIONED SURFACE BOUNDARY WILL LINGER ACROSS THE TRI-STATE
AREA THIS WEEKEND. THIS FRONT, STACKED ON TOP BY A LOW-LVL FRONTAL
ZONE, AS WELL AS SOMEWHAT PERSISTENT DIVERGENCE FROM THE RIGHT
ENTRANCE REGION OF AN UPPER JET, WILL KEEP SCATTERED RAIN CHANCES
AND QUITE A BIT OF CLOUD COVER THROUGH THE AREA DURING THE WEEKEND.
NOW THE DEGREE OF RAIN COVERAGE IS STILL UP IN THE AIR, GIVEN
SOMEWHAT DIFFUSE AND TRANSIENT LIFT AT TIMES, BUT ALSO SOME SUB
CLOUD DRY AIR THAT COULD LINGER. SO WILL CONTINUE TO ADVERTISE
A NARROW STRIPE OF LOW TO MID-RANGE POPS THAT WILL FLUCTUATE
NORTH AND SOUTH WITH THE MOVEMENT OF THE LOW-LVL BAROCLINIC
ZONE.
TEMPERATURES WILL BE QUITE TRICKY ON SATURDAY AS THE FRONT BISECTING
THE CWA COULD LEAD TO A LARGE TEMPERATURE DISCREPANCY FROM
HURON TO STORM LAKE. 12Z GUIDANCE HAS TRENDED DOWNWARDS WITH
HIGHS SLIGHTLY, SO BLENDED IN SHORT TERM GUIDANCE TO ACCOUNT FOR
TRENDS THE NBM MAY NOT HAVE CAUGHT ONTO YET. THERE SEEMS TO BE
MUCH MORE CONSISTENCY IN GUIDANCE THAT COOLER AIR MAY SINK
FURTHER SOUTH BEHIND THE FRONT FOR SUNDAY. WITH A PERSISTENT AND
COOL NORTHEAST SURFACE FLOW IN THE CWA, HIGHS MAY STRUGGLE TO
BREAK THE 50S IN PORTIONS OF THE CWA WITH THE WARMEST HIGHS NEAR
HIGHWAY 20.
MONDAY-TUESDAY: SLIGHT DISCREPANCIES IN MEDIUM RANGE GUIDANCE ON
THURSDAY HAVE RESOLVED SOMEWHAT THIS MORNING. THE LARGE UPPER
TROUGH IN THE FOUR CORNER BEGINS TO EJECT NORTHEAST LATE SUNDAY
INTO MONDAY, AND WILL BEGIN TO ENHANCED WARM ADVECTION
NORTHWARD AND INCREASE THE INTENSITY OF THE LOW-LVL FRONTAL ZONE
THROUGH THE CWA BY MONDAY MORNING. WE'LL HAVE TO WATCH FOR ANY
POTENTIAL INSTABILITY ARRIVAL, BUT FAIRLY WIDESPREAD MODERATE
RAIN MAY BEGIN TO FORM MONDAY MORNING AND GRADUALLY RETREAT
NORTHWARD AS THE UPPER TROUGH ENTERS THE PLAINS.
LATEST GFS GUIDANCE HAS SHIFTED THE TRACK OF THE UPPER LOW SLIGHTLY
FURTHER NORTHWEST FROM THE NEBRASKA PANHANDLE INTO CENTRAL SOUTH
DAKOTA BY MONDAY NIGHT, CLOSELY RESEMBLING THE LATEST ECMWF RUNS. AI
BASED MODELS ARE ALSO VERY SIMILAR IN THEIR TRACK OF THIS UPPER WAVE
(PERHAPS A BIT FURTHER SOUTH THAN DETERMINISTIC RUNS), SUGGESTING
WIDESPREAD RAIN WILL CONTINUE INTO TUESDAY MORNING AS THE SYNOPTIC
TROUGH PASSES.
ALL-IN-ALL, THIS MULTI-DAY RAIN EVENT IS EXPECTED TO BRING RAIN
TO NEARLY THE ENTIRE REGION, AND IN SOME CASES, MEANINGFUL
RAINFALL TOTALS. THE LATEST PROBABILITIES FROM THE ECE/GEFS FOR
>0.50" ARE ALL NEAR 100% BY TUESDAY MORNING, WITH 1.0"
PROBABILITIES >80%, AND PROBABILITIES FOR 2-3" OF RAIN AROUND
30%. THE LOCATION MAY CHANGE, BUT THE AREA WITH THE GREATEST
POTENTIAL FOR THE HIGHEST TOTALS MAY FALL BETWEEN I-90 AND THE
MISSOURI RIVER WEST OF I-29.
MONDAY'S HIGH TEMPERATURES WILL BE HIGHLY DEPENDING ON THE TRACK OF
THE UPPER LOW AND ASSOCIATED SURFACE CYCLOGENESIS AND LOW TRACK.
AREAS STUCK UNDER MODERATE RAIN MAY BE IN THE 40S, WITH AREAS WHERE
RAIN LIFTS NORTH COULD RISE INTO THE 50S.
WEDNESDAY-THURSDAY: IT APPEARS A SECOND SYSTEM MAY RACE THROUGH THE
NORTHERN US ON THE HEELS OF MONDAY/TUESDAY UPPER TROUGH BY TUESDAY
NIGHT AND WEDNESDAY. WE'LL SEE HOW QUICKLY MOISTURE CAN WORK IT'S
WAY BACK NORTHWARD, BUT THIS SECOND SYSTEM ALSO POSES A REASONABLE
RISK FOR RAINFALL IN THE MIDDLE OF THE WEEK ALONG WITH A SLIGHT
UPWARDS BUMP IN TEMPERATURES TOWARDS NORMAL.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 637 PM CDT FRI OCT 23 2026
BREEZY CONDITIONS WITH SOUTHERLY GUSTS OF 20-30 KTS WILL
CONTINUE THROUGH MOST OF THE PERIOD, THOUGH WE WILL GRADUALLY
SEE A DOWNTREND IN WINDS AS THE NIGHT AND DAYTIME ON SATURDAY
PROGRESSES. THE EXCEPTION WILL BE NEAR AND WEST OF THE JAMES
RIVER WHERE A SECONDARY PUSH OF STRONGER GUSTS TOWARDS 35-40
KTS WILL FOLLOW A COLD FRONTAL PASSAGE AROUND AND JUST AFTER
SUNRISE SATURDAY.
ALSO TONIGHT, SOME MAINLY DIRECTIONAL LOW LEVEL WIND SHEAR WILL
BE PRESENT GIVEN THE SOUTHWESTERLY LOW LEVEL JET. AN EASTWARD
MOVING COLD FRONT WILL ENTER CENTRAL SOUTH DAKOTA BY DAYBREAK,
TURNING SURFACE WINDS TO THE NORTHWEST AREA-WIDE AS IT MOVES
THROUGH DURING THE DAYTIME HOURS ON SATURDAY. LASTLY REGARDING
WINDS, GUSTS WILL DIMINISH BELOW 20 KTS FOR EVERYONE BY THE LAST
FEW HOURS OF THE PERIOD.
RAIN CHANCES WILL INCREASE LATE TONIGHT INTO TOMORROW MORNING FOR
AREAS MAINLY BETWEEN I-29 AND THE JAMES RIVER, THOUGH EXACT
PLACEMENT OF WHERE THIS ACTIVITY DEVELOPS REMAINS A BIT
UNCERTAIN. THUS, PROB30 GROUPS FOR SHOWERS AT KFSD AND KHON
MAKE THE MOST SENSE AT THIS TIME. THUNDER CHANCES ARE LOW WITH
THIS ACTIVITY (LESS THAN 20%), BUT CAN'T ENTIRELY BE RULED OUT.
AS WE HEAD THROUGHOUT THE DAY ON SATURDAY, ADDITIONAL SHOWERS
LOOK TO DEVELOP, THOUGH THUNDER CHANCES WILL DIMINISH BELOW 15%
AS WE HEAD THROUGHOUT THE DAY.
CLIMATE
ISSUED AT 1218 PM CDT FRI OCT 23 2026
A VERY WARM DAY WILL STILL BRING THE POTENTIAL FOR RECORD HIGH
MINIMUM TEMPERATURES ON FRIDAY. SIOUX CITY AND SIOUX FALLS HAVE
ALREADY DROPPED LOWER THAN THEIR RECORD FOR THE DATE, HOWEVER HURON
DROPPED TO 62, SO POTENTIAL FOR TYING OR BREAKING THIS RECORD
REMAINS POSSIBLE.
OCTOBER 23:
KFSD: 60/1963
KSUX: 65/1899
KHON: 52/1963
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SAMET
DISCUSSION...DUX
AVIATION...SAMET
CLIMATE...DUX
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