852
FXUS63 KFSD 041746
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1146 AM CST WED MAR 4 2026
KEY MESSAGES
- FOG, WITH SOME DENSE FOG AND VISIBILITY BELOW ONE QUARTER
MILE, IS EXPECTED AGAIN TONIGHT.
- A STRONG STORM SYSTEM BRINGS WIDESPREAD SHOWERS AND A FEW
THUNDERSTORMS TO THE REGION THURSDAY NIGHT INTO FRIDAY.
CHANCES OF MORE THAN A HALF INCH OF RAIN ARE OVER 50% FROM
ABOUT YANKTON TO WINDOM SOUTHEAST.
- A FEW STRONG TO SEVERE STORMS ARE POSSIBLE THURSDAY NIGHT
THROUGH FRIDAY. MAIN RISK AREA IS SOUTH OF I-90, WITH LARGE
HAIL CURRENTLY THE MAIN HAZARD.
- TEMPERATURES FALLING BEHIND THE COLD FRONT FRIDAY NIGHT INTO
SATURDAY CAUSES RAIN TO SWITCH TO SNOW. LIGHT TO POSSIBLY
MODERATE ACCUMULATIONS POSSIBLE FROM SOUTH CENTRAL TO
NORTHEASTERN SOUTH DAKOTA. CONFIDENCE IN EXACT AMOUNTS IS LOW.
DISCUSSION
ISSUED AT 240 AM CST WED MAR 4 2026
DENSE FOG WITH VISIBILITY BELOW ONE QUARTER OF A MILE CONTINUES TO
EXPAND THIS MORNING. OBSERVATIONS AND LOCAL DOT CAMERAS SHOW THAT
CONDITIONS ARE QUITE VARIABLE OVER SHORT DISTANCES, SO BE PREPARED
FOR QUICKLY CHANGING VISIBILITY THROUGH THE WEDNESDAY MORNING
COMMUTE. TEMPERATURES NEAR TO BELOW FREEZING MAY LEAD TO SOME
ISOLATED SLICK SPOTS. DENSE FOG ADVISORIES ARE IN EFFECT FOR MUCH OF
THE AREA THROUGH 8 AM CST, BUT WOULD NOT BE SURPRISED TO SEE
CONTINUED EXPANSION AND EXTENSION THROUGH THE MORNING HOURS IF
TRENDS CONTINUE. FOG AND STRATUS MAY BE SLOWER TO CLEAR THAN SOME OF
THE CURRENT GUIDANCE SUGGEST, WHICH COULD LEAD TO TEMPERATURES A
COUPLE OF DEGREES COOLER THAN CURRENT FORECAST. HIGHS STILL WARM
WELL ABOVE AVERAGE INTO THE 50S AND 60S.
CAN'T ENTIRELY RULE OUT A STRAY SPRINKLE THIS EVENING SOUTH OF US
HWY 20 AND INTO NORTHWESTERN IA; HOWEVER, CONFIDENCE IS LOW ENOUGH
IN OCCURRENCE WITH DRY SUB CLOUD LAYER AND BETTER FORCING TO THE
SOUTHEAST AS THE WAVE MOVES THROUGH IA TO KEEP OUT OF THE FORECAST.
STRATUS AND FOG, POSSIBLY DENSE FOG, IS EXPECTED TO DEVELOP AGAIN
LATE TONIGHT INTO THURSDAY MORNING. TEMPERATURES NEAR FREEZING WITH
FOG COULD AGAIN LEAD TO SOME SLICK SPOTS INTO THE THURSDAY MORNING
COMMUTE.
MID AND UPPER LEVEL TROUGH EJECTS OUT OF THE ROCKIES BEGINNING
THURSDAY AND THROUGH THE DAY FRIDAY. INCREASING SOUTHERLY FLOW AHEAD
OF THE COLD FRONT ALLOWS TEMPERATURES THURSDAY TO WARM INTO THE 60S.
STRONG WINDS ESPECIALLY WEST OF I-29 AND DRY CONDITIONS WILL LEAD TO
SOME ELEVATED FIRE DANGER. HUMIDITY VALUES ABOVE 30% SHOULD HELP
LIMIT ANY NEAR CRITICAL CONDITIONS, BUT VERY HIGH FIRE DANGER IS
EXPECTED.
AS THE TROUGH MOVES EAST INTO THURSDAY NIGHT, CHANCES FOR CONVECTION
INCREASES. LLJ STRENGTHENS AS LEE CYCLOGENESIS OCCURS ACROSS THE
WESTERN PORTIONS OF NE/KS. FOR US, THAT MEANS AMPLE MOISTURE
ADVECTION AS SOUTHERLY FLOW ALOFT AND AT THE SURFACE CONTINUES.
ALTHOUGH WE'LL HAVE THE LLJ IN PLACE AND STRENGTHENING OVERNIGHT,
ONE QUESTION REMAINS IS HOW MUCH INSTABILITY THERE WILL BE. GUIDANCE
SHOWS MOST OF THE AREA WITH AROUND 500 J/KG OF MUCAPE THURSDAY NIGHT
INTO FRIDAY MORNING, ALTHOUGH THERE ARE POCKETS OF OVER 1000 J/KG
EARLY IN THE OVERNIGHT ACROSS NORTHWESTERN IA. GIVEN ALL THIS, 0-6
KM BULK SHEAR AROUND 35 KNOTS, AND STEEP MID LEVEL LAPSE RATES OVER
7 DEG C/KM, EXPECT STORMS TO BE ELEVATED WITH THE MAIN THREAT BEING
LARGE HAIL WITH POSSIBLY AN OCCASIONAL SEVERE WIND GUST. SURFACE
COLD FRONT CONTINUES TO MOVE EAST THROUGH FRIDAY, SO MAY SEE THE
SEVERE THREAT CONTINUE INTO THE DAY. BULK SHEAR AND LAPSE RATES
REMAIN FAIRLY SIMILAR, BUT MAY SEE INSTABILITY INCREASE DEPENDING ON
THE TIMING OF THE FRONT. BOTH OF THESE RISKS ARE COVERED BY SPC DAY
2 AND 3 OUTLOOKS.
AS FOR RAINFALL AMOUNTS, AMOUNTS WILL VARY QUITE A BIT WITH THE
CONVECTION. ENSEMBLE GUIDANCE CONTINUES TO SHOW LOW TO MODERATE (25-
60%) CHANCES OF EXCEEDING 0.5" OF LIQUID THROUGH SATURDAY MORNING,
HIGHEST ACROSS NORTHWESTERN IA AND EAST (OVER 50% ALONG AND EAST OF
A YANKTON TO WINDOM LINE).
STILL SOME TIMING DIFFERENCES ON THE FRONT, BUT FALLING TEMPERATURES
WILL ALLOW FOR PRECIPITATION TO CHANGE TO SNOW FRIDAY EVENING/NIGHT
WITH LIGHT TO POSSIBLY MODERATE ACCUMULATIONS POSSIBLE - MAINLY FROM
NORTHWESTERN NE TO SOUTH CENTRAL SD TO NORTHEASTERN SD INTO MN.
ACCUMULATIONS WILL BE HIGHLY DEPENDENT ON HOW QUICKLY COLD AIR
SWEEPS IN, SO DEFINITELY KEEP ON EYE ON THINGS IF YOU HAVE REGIONAL
TRAVEL PLANS INTO SATURDAY. ACCUMULATIONS MAY BE SHORT LIVED,
DEPENDING ON HOW MUCH WE RECOVER WITH A QUICK SURFACE AND THERMAL
RIDGE SLIDING THROUGH SATURDAY.
WARMER TEMPERATURES AND DRY CONDITIONS CONTINUE THROUGH THE WEEK.
PRECIPITATION CHANCES RETURN EARLY TO MID NEXT WEEK, ALTHOUGH
DETAILS ARE STILL UNCLEAR.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1144 AM CST WED MAR 4 2026
STRATUS IS BEGINNING TO BREAK UP AND CEILINGS LIFT AS OF TAF
ISSUANCE. CURRENTLY THERE IS A MIX OF VFR DOWN TO LIFR CEILINGS.
THESE WILL SLOWLY IMPROVE THROUGH THE EARLY PART OF THIS AFTERNOON.
WINDS ARE FROM THE SOUTH AND BREEZY WITH GUSTS OF 20-25 KTS FOR
AREAS WEST OF THE JAMES RIVER AND NORTH OF SOUTH DAKOTA 34.
ELSEWHERE WINDS ARE GENERALLY LIGHT. WINDS ARE EXPECTED TO DECREASE
LATE THIS AFTERNOON AND BECOME MORE SOUTHEASTERLY.
CONFIDENCE IS INCREASING FOR STRATUS AND FOG REDEVELOPING TONIGHT,
THE BIGGEST QUESTION IS WHERE. CURRENT NBM GUIDANCE KEEPS FOG ALONG
AND EAST OF I-29. CAMS GUIDANCE AND SOUNDINGS BOTH INDICATE THAT FOG
IS POSSIBLE AS FAR WEST AS CENTRAL SOUTH DAKOTA. WINDS OUT HERE WILL
REMAIN SLIGHTLY ELEVATED, AND THIS MAY IMPEDE THE FOG
DEVELOPMENT. HOWEVER, CONFIDENCE IS HIGH ENOUGH TO HAVE PUT A
MENTION OF MVFR VISIBILITY IN KHONS TAF FOR THURSDAY MORNING.
KFSD AND KSUX CONFIDENCE IN FOG IS MODERATE TO HIGH, AND HAVE
INCLUDED MENTION OF IFR CEILING AND VISIBILITIES.
SOUTHEASTERLY WINDS INCREASE THROUGH THE LATE MORNING THURSDAY,
PEAKING AROUND MID DAY WITH GUSTS OF 24-27 KTS. HIGHEST GUSTS WILL
BE WEST OF I-29. TO THE EAST GUSTS PEAK BETWEEN 18-22 KTS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...SG
AVIATION...AJP
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