515
FXUS63 KFSD 031712
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1212 PM CDT FRI APR 3 2026
KEY MESSAGES
- A WINTRY MIX BEGINS TONIGHT AND CONTINUES INTO SATURDAY
AFTERNOON.
- LIGHT ELEVATED AND BRIDGE ICING WILL BE POSSIBLE ALONG AND NORTH
OF I-90. SNOW TOTALS OF A DUSTING TO A COUPLE INCHES WILL BE
POSSIBLE ALONG HIGHWAY 14.
- WRAP AROUND SNOW SATURDAY MORNING ALONG WITH OCCASIONAL GUSTY
CONDITIONS MAY BRING BRIEF SLICK ROADS.
- DRY, BUT COOLER THAN NORMAL TEMPERATURES RETURN INTO NEXT
WEEK.
UPDATE
ISSUED AT 705 AM CDT FRI APR 3 2026
NORTHEAST FLOW HAS ALLOWED SLIGHTLY LOWER DEW POINTS AND
TEMPERATURES TO FILTER INTO THE AREA EARLY THIS MORNING. THIS
COULD ALLOW FOR A BROADER AREA OF LIGHT ICING FROM I-90 TO
PERHAPS AS FAR SOUTH AS THE HIGHWAY 18 CORRIDOR BEFORE SURFACE
TEMPERATURES REBOUND BACK ABOVE FREEZING LATER THIS MORNING.
MORNING COMMUTERS SHOULD BE PREPARED FOR SCATTERED SLICK SPOTS,
ESPECIALLY ON ELEVATED AREAS SUCH AS BRIDGE DECKS AND OTHER
UNTREATED SURFACES.
ISSUED AT 1244 AM CDT FRI APR 3 2026
THE FORECAST REMAINS LARGELY ON TRACK FOR A LATE WINTER STORM SYSTEM
TO IMPACT THE REGION. THE TRICKY PART IS STILL THE PRECIPITATION
TYPES (P-TYPE) AT THE SURFACE. SOUNDINGS INDICATE A TYPICAL MIXED
PRECIPITATION SET UP WITH A WARM LAYER ATOP A COLD SURFACE LAYER
HOVERING AROUND FREEZING. THE DEPTH AND DURATION OF THE WARM LAYER
VARIES WIDELY FROM LOCATION TO LOCATION AND WILL HAVE A HUGE IMPACT
ON ACCUMULATIONS. FOR AREAS NORTH OF I-90, SURFACE TEMPERATURES ARE
EXPECTED TO FALL BELOW FREEZING FOR THE FASTEST, WHICH WILL
MEAN THE MOST LIKELY P-TYPE AT ONSET WILL BE FREEZING
RAIN/DRIZZLE TO ICE PELLETS. AS THE SYSTEM PROGRESSES EAST OVER
THE NEXT 24 HOURS CAA WILL EVENTUALLY COOL THE WARM LAYER AND
SURFACE TEMPERATURES TO BELOW FREEZING. AT THIS POINT THERE WILL
BE A TRANSITION TO SLEET, AND EVENTUALLY SNOW. ANOTHER SNAG TO
BE ON THE LOOK OUT FOR IS SOUNDINGS INDICATE INTERMITTENT LOSS
OF SATURATION IN THE DGZ, WHICH COULD RESULT IN TRANSITIONS
FROM SNOW TO FREEZING DRIZZLE AND BACK. FOR AREAS SOUTH OF I-90
LIGHT RAIN IS THE MOST LIKELY P-TYPE AT ONSET. AGAIN, THE
INTERMITTENT LOSS OF SATURATION COULD RESULT IN PERIODS OF
DRIZZLE TO FREEZING DRIZZLE AND BACK AS TEMPERATURES DECREASE.
RAIN TOTALS WILL BE LIGHT, BETWEEN 0.05" TO 0.20".
WHILE THE WHOLE REGION MAY SEE AT LEAST SOME FREEZING RAIN/DRIZZLE,
THE AREAS MOST LIKELY TO SEE ACCUMULATING ICE ON SURFACES ARE NORTH
OF I-90. POTENTIALLY IMPACTFUL ACCUMULATION OF 0.10" TO 0.20" OF ICE
LIE ALONG A ROUGH LINE FROM WESSINGTON SPRINGS IN SOUTH DAKOTA EAST
TO JEFFERS MINNESOTA AND NORTH. SNOW TOTALS HAVE HELD STEADY WITH 1-
3 INCHES POSSIBLE ALONG AND NORTH OF A LINE FROM CHAMBERLAIN TO DE
SMET. SOUTH OF THERE GENERALLY LESS THAN AN INCH WITH AMOUNTS
DECREASING AS YOU HEAD SOUTH. CONSIDERING ALL THIS THE CURRENT
WINTER WEATHER ADVISORY LOOKS TO BE IN GOOD SHAPE. THERE IS ALSO THE
QUESTION OF ROAD TEMPERATURES. YESTERDAY WE SAW MOST FROZEN
PRECIPITATION MELTING AND ONLY ACCUMULATING ON ELEVATED SURFACES
SUCH AS BRIDGES AND ROAD SIGNS. THE SAME WILL LIKELY BE TRUE TODAY
DURING DAYLIGHT HOURS. AFTER SUNSET SURFACE TEMPERATURES FALL
RAPIDLY BELOW FREEZING. WET ROADWAYS AND SIDEWALKS MAY BECOME
SLIPPERY. PRECIPITATION PUSHES NORTHEAST THROUGH THE OVERNIGHT
FRIDAY AND CEASE FROM WEST TO EAST THROUGH SATURDAY AFTERNOON
AFTERNOON.
ONE FINAL ITEM TO KEEP A WATCH ON FOR FRIDAY IS THE CHANCE FOR
ISOLATED TO SCATTERED THUNDERSTORMS OVER NORTHWEST IOWA MID TO LATE
FRIDAY MORNING. ELEVATED INSTABILITY BETWEEN ROUGHLY 500-1000 J/KG
MUCAPE, LAPSE RATES AROUND 7 C/KM, AND WEAK SHEAR OF AROUND 25 KTS
COULD WORK WITH STRONG WAA AHEAD OF AN APPROACHING WARM FRONT TO
PRODUCE THUNDERSTORMS. MAIN THREAT WOULD BE SMALL HAIL, THOUGH A FEW
STRONGER STORMS COULD PRODUCE HAIL TO THE SIZE OF A QUARTER.
DISCUSSION
ISSUED AT 152 PM CDT THU APR 2 2026
THIS AFTERNOON: WE'RE CONTINUING TO WATCH THIS INITIAL
SHORTWAVE MOVE EAST OF THE CWA EARLY THIS AFTERNOON. WEAK
ISENTROPIC DOWNGLIDE WILL BRING END END TO THE PRECIPITATION IN
MOST LOCATIONS, WITH REPORTS OF MINOR ELEVATED ICING REPORTED
OVER PORTIONS OF SW MINNESOTA AND THE I-29 CORRIDOR OF EASTERN
SD. MRMS RADIAL FREEZING RAIN ACCUMULATIONS ALSO SUPPORT THIS,
WITH FAIRLY LOCALIZED 0.10" TOTALS THROUGH THE RIDGE AREAS. WHILE
A LOW PROBABILITY, PATCHY DRIZZLE OR FREEZING DRIZZLE MAY STILL
DEVELOP THIS AFTERNOON. TEMPERATURE REMAIN NEAR OR ABOVE
FREEZING IN MOST AREAS.
TONIGHT: WINDS WILL TURN LIGHT AND VARIABLE LATER THIS EVENING AS
SURFACE RIDGING SLIDES EAST. LATEST SHORT TERM GUIDANCE KEEPS
EXTENSIVE CLOUD COVER THROUGH THE REGION WHICH MAY KEEP TEMPERATURE
A BIT WARMER THAN THE NBM INITIALLY SUGGESTED. WE'LL HAVE TO WATCH
THE IMPACTS OF A COLDER NE WIND OUT OF CENTRAL MN THAT COULD BRING
IN MINOR SURFACE COLD ADVECTION BY DAYBREAK. A DEEPER UPPER TROUGH
MOVING INTO THE CENTRAL ROCKIES WILL SPREAD SCATTERED THROUGH
NORTHERN NEBRASKA AND CENTRAL SOUTH DAKOTA BY MIDNIGHT. ADDITIONAL
SCATTERED SHOWERS WILL DEVELOP SOUTHEAST INTO NORTHERN IOWA BY
DAYBREAK WITHIN A CORRIDOR OF MODEST LOW-LVL WARM ADVECTION FROM THE
SE. TEMPERATURES WILL BE CRITICAL TO SURFACE IMPACTS, WITH SOME
SHIFT NORTHWARD IN WARMER TEMPERATURES REDUCING ICING SOUTH OF I-90.
FRIDAY: TWO THINGS TO WATCH ON FRIDAY. FIRST WILL BE EASTWARD
SPREAD OF SHOWERS THROUGH THE TRI-STATE AREA AFTER DAYBREAK. LATEST
SOUNDINGS CONTINUE TO SHOW A FAVORED TREND TOWARDS PARTIAL TO FULL
MELTING OF FALLING HYDROMETEORS, PUSHING FAVORITE P-TYPES TOWARDS
RAIN AND SLEET. SURFACE TEMPERATURES WILL BE CRITICAL ONCE AGAIN,
THOUGH AS WE'VE SEEN TODAY, WARM ROAD AND GROUND TEMPERATURES
ARE PREVENTING MUCH IN THE WAY OF ICING ON ROADS (EXCEPT FOR
BRIDGES). MOST ICING IS LIKELY TO REMAIN ON ELEVATED COOLED
SURFACES. AT THIS TIME, ICING IS MORE LIKELY NORTH OF I-90, WITH
MEANINGFUL ICING ALONG HIGHWAY 14 INTO SW MINNESOTA. SHOULD
COLDER AIR DEEPEN INTO CENTRAL SOUTH DAKOTA EARLY FRIDAY, A
QUICK 1-3" OF SNOW COULD FALL ALONG A LINE FROM CHAMBERLAIN TO
HURON. WILL ISSUE A WINTER WEATHER ADVISORY FOR PORTIONS OF THE
CWA NORTH OF I-90. LATER FORECASTS WILL NEED TO CLOSELY MONITOR
THE TEMPERATURES INTO THE OVERNIGHT FOR ANY POTENTIAL
ADJUSTMENTS TO ICING.
THE SECOND THING TO WATCH IS A NARROW CORRIDOR OF ELEVATED
INSTABILITY ROOTED AT THE 800 MB LAYER THAT COULD APPROACH 1000
J/KG. THE INTENSIFICATION OF FOCUSED WARM ADVECTION AND A SHARP
CONVERGENCE ZONE COULD LEAD TO ISOLATED TO SCATTERED
THUNDERSTORMS MOVING THROUGH NW IOWA AND INTO SOUTHERN MINNESOTA
BY MID-MORNING. EFFECTIVE SHEAR IS MINIMAL, BUT WITH FREEZING
LEVELS BETWEEN 9-10K FT AGL, SMALL HAIL TO ISOLATED QUARTER HAIL
COULD BE POSSIBLE.
FRIDAY NIGHT: AS THE UPPER TROUGH MOVES INTO THE DAKOTAS AND
CONTINUES TO DEEPEN, AN EXPANSIVE DRY SLOT WILL MOVE THROUGH THE TRI-
STATE AREA, POTENTIALLY SHUTTING OFF PRECIPITATION OR CONVERTING IT
OVER TO DRIZZLE. LATEST GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR
LIGHT SNOW TO PIVOT AROUND THE UPPER TROUGH INTO SATURDAY MORNING,
THROUGH GUIDANCE HAS BACKED OFF ON THE SOUTHWARD EXTEND OF THIS
PRECIPITATION TODAY.
SATURDAY: WE'LL SEE STRONGER COLD ADVECTION MOVE THROUGH THE AREA
SATURDAY AS THE TROUGH CROSSES INTO MN/WI. SOME QUESTIONS ABOUT
POTENTIAL FOR A FEW CONVECTIVE SNOW SHOWERS REMAIN FOR SATURDAY
AFTERNOON, THOUGH SOUNDINGS DO NO SEEM TO BE AS AGGRESSIVE WITH
LAPSE RATES BY THE AFTERNOON. NEVERTHELESS, AFTERNOON GUSTS TO
30 TO 35 MPH MAY BE POSSIBLE.
SUNDAY-WEDNESDAY: MOSTLY QUIET CONDITIONS ARE EXPECTED WELL INTO
NEXT WEEK AS MID-LVL HEIGHTS GRADUALLY RISE OVER THE WEST COAST.
TEMPERATURES THROUGH MONDAY WILL BE COLDER THAN NORMAL AS CANADIAN
HIGH PRESSURE DRAINS INTO THE PLAINS. A QUICK FLIP AROUND TO GUSTY
SOUTHERLY WINDS IS EXPECTED TUESDAY AFTERNOON BUT THANKFULLY AFTER
WIDESPREAD PRECIPITATION FIRE WEATHER RISKS WILL BE MUCH LOWER. A
BRIEF SURGE OF WARM AIR ALOFT ARRIVES ON WEDNESDAY AND MAY PROVIDE
OUR ONLY CHANCE OF EXCEEDING NORMAL THIS WEEK. PRECIPITATION
CHANCES RISE AGAIN BY THURSDAY.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1210 PM CDT FRI APR 3 2026
WIDESPREAD IFR CONDITIONS IN STRATUS AND PATCHY DRIZZLE WILL BE
FAIRLY COMMON THROUGH MUCH OF THE PERIOD. NORTH OF I-90 MIXED
PRECIPITATION WILL BE MORE LIKELY, ESPECIALLY TONIGHT INTO
SATURDAY MORNING, ALTHOUGH LATER TONIGHT INTO SATURDAY MORNING
THE MAIN PRECIPITATION TYPE SHOULD BE SNOW. NORTHWEST WINDS WILL
BEGIN TO INCREASE LATER TONIGHT AND CONTINUE INTO SATURDAY, WITH
GUSTS OF 20 TO 40 MPH LIKELY SATURDAY.
FSD WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR SDZ038>040-
052>058.
MN...WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR MNZ071-072-
080-081-097.
IA...NONE.
NE...NONE.
UPDATE...AJP
DISCUSSION...DUX
AVIATION...08
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