767
FXUS63 KFSD 131147
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
647 AM CDT MON APR 13 2026
KEY MESSAGES
- PATCHY AND LOCALLY DENSE FOG CONTINUES THROUGH THE MID MORNING
HOURS. EXPECT VISIBILITY BELOW ONE MILE IN THE DENSEST FOG.
- ELEVATED FIRE DANGER THIS AFTERNOON AND EVENING ACROSS SOUTH
CENTRAL SOUTH DAKOTA WITH HUMIDITY BELOW 20% AND WEST WIND
GUSTS AROUND 20 MPH.
- THUNDERSTORMS RETURN THIS AFTERNOON AND EVENING. SCATTERED
STRONG TO SEVERE STORMS EXPECTED - GREATEST RISK FOR
SOUTHWESTERN MINNESOTA INTO ADJACENT AREAS OF SOUTH DAKOTA AND
IOWA. TIMING OF GREATEST CONCERN IS 4 TO 10 PM.
- MAIN HAZARDS ARE LARGE HAIL TO 2 INCHES IN DIAMETER AND WIND
GUSTS TO 70 MPH. A TORNADO OR TWO ARE ALSO POSSIBLE. HAVE A
SEVERE WEATHER PLAN AND MULTIPLE WAYS TO RECEIVE WARNINGS.
- PERIODIC CHANCES (20-60%) FOR SHOWERS AND THUNDERSTORMS
CONTINUE THIS WEEK. DETAILS REMAIN UNCERTAIN AT THIS TIME.
UPDATE
ISSUED AT 330 AM CDT MON APR 13 2026
AREA OF SHOWERS AND ISOLATED STORMS CONTINUES TO MOVE NORTHEAST OUT
OF NE THIS MORNING. SO FAR, HAVE ONLY SEEN A COUPLE OF SPRINKLES ON
AREA DOT AND PARTNER CAMERAS, AND SOUNDINGS SHOW A DRY SUB CLOUD
LAYER SO NOT SURPRISED TO SEE LIMITED PRECIPITATION THIS MORNING.
EXPECT THESE TO CONTINUE WITH WAA/WAVE. WATCHING STRATUS AND FOG
DROP SOUTH ALONG THE MN/SD BORDER TO US HWY 14 AS WELL, REDUCING
VISIBILITY. PATCHY RADIATION FOG IS DEVELOPING ACROSS NORTHWESTERN
IA WHERE SKIES ARE CLEAR, WHICH HAS DROPPED SOME VISIBILITY TO LESS
THAN 2 MILES. FINALLY, WATCHING WHAT APPEARS TO BE THE WARM FRONT
LIFT NORTH OF I-90 ON RADAR, WHICH WILL BE A CATALYST FOR STORMS
LATER TODAY.
ALTHOUGH THE MAIN FOCUS OF THE FORECAST REMAINS ON THE SEVERE
WEATHER POTENTIAL LATER TODAY, DO NEED TO MENTION THE ELEVATED FIRE
CONCERNS ACROSS SOUTH CENTRAL SD THIS AFTERNOON/EVENING WITH MINIMUM
HUMIDITY VALUES BELOW 20%. LIMITING FACTOR FOR WIDESPREAD OR
SIGNIFICANT CONCERN IS THE WIND - WITH GUSTS AROUND 20 MPH.
MAIN FOCUS OF THE FORECAST REMAINS ON THE SEVERE WEATHER POTENTIAL
LATER TODAY AND THROUGH THIS EVENING. FORECAST IS GENERALLY ON TRACK
FROM YESTERDAY AND EARLIER UPDATES. BIGGEST QUESTION CONTINUES TO BE
WHERE THE SURFACE WARM FRONT IS GOING TO SET UP AND THE RESULTANT
DRY LINE AND TRIPLE POINT ARE LOCATED. VARIANCE ON THE WARM FRONT
STILL RANGES FROM THE I-90 CORRIDOR TO NEAR/NORTH OF THE US HWY 14
CORRIDOR. SOME QUESTION IF ANY OF THE MORNING SHOWERS/STORMS AND
CLOUD COVER MAY IMPACT WARMING AND THEREFORE INSTABILITY LATER AND
IF SO - WHERE WITH CAMS STILL SHOWING A COUPLE DIFFERENT AREAS OF
DEVELOPMENT AND QUITE VARIED ON THE LOCATION OF BOTH AREAS. SURFACE
LOW AND SUPPORTING MID/UPPER WAVES ARE BOTH STILL PROGGED TO MOVE
OUT OF NE INTO OUR FORECAST AREA BY EARLY TO MID AFTERNOON (2-4 PM)
WITH THE MID/UPPER WAVE SLIGHTLY LAGGED, LIKELY LEADING TO THE CAMS
SHOWING 2 AREAS OF DEVELOPMENT. AMPLE SHEAR AND STEEP LAPSE RATES
LEAD TO LARGE 2 INCH HAIL AS THE MAIN HAZARD, WITH DAMAGING WIND
GUSTS TO 70 MPH. WITH THE WARM FRONT IN PLAY AND THE POTENTIAL FOR
SUPERCELLS, A TORNADO OR TWO CANNOT BE RULED OUT. INITIAL
DEVELOPMENT OF SUPERCELLS MAY GROW UPSCALE WITH THE 0-6KM SHEAR
SOMEWHAT PARALLEL TO THE WARM FRONT. KEEP AN EYE ON THE FORECAST
TODAY AND STAY WEATHER AWARE.
DISCUSSION
ISSUED AT 243 PM CDT SUN APR 12 2026
FIRE DANGER PERSISTS THIS AFTERNOON ALONG AND WEST OF I-29. MORE
DETAILS CAN BE FOUND IN THE FIRE WEATHER DISCUSSION BELOW. BREEZY
WESTERLY WINDS PERSIST WITH HIGH TEMPERATURES WARMING TO THE 70S TO
LOW 80S, MAKING FOR A WARM APRIL DAY. FIRE DANGER WILL COME TO AN
END THIS EVENING AS TEMPERATURES COOL AND WINDS WEAKEN. LOW
TEMPERATURES WILL FALL TO THE UPPER 40S AND 50S OVERNIGHT.
WINDS WILL TURN TO OUT OF THE SOUTH/SOUTHEAST ON MONDAY, RESULTING
IN MOIST SOUTHERLY FLOW AND MOISTENING DEW POINTS BACK INTO THE 40S,
50S, AND EVEN LOW 60S. HIGH TEMPERATURES WILL WARM TO THE UPPER 70S
AND 80S ACROSS THE AREA AS A WARM FRONT PUSHES NORTHWARDS. THERE
REMAINS UNCERTAINTY IN WHERE THE WARM FRONT SETS UP. SOME OF THE
LATEST HI-RES MODELS BRING THE WARM FRONT TO THE VICINITY OF HIGHWAY-
14. SOME PUSH THE FRONT JUST NORTH OF THE HIGHWAY WHILE OTHERS ARE
JUST SOUTH. THIS WILL HAVE A BIG EFFECT ON ANY SEVERE STORM
POTENTIAL DURING THE AFTERNOON HOURS TOMORROW. A STOUT ELEVATED
MIXED LAYER (EML) WILL BE IN PLACE. SOUNDING CLIMATOLOGY WOULD PLACE
THIS EML AT THE VERY TOP OF CLIMATOLOGY FOR THIS TIME OF YEAR! THIS
EML WILL RESULT IN CAPPING ACROSS THE WARM SECTOR, LIMITING MORE
WIDESPREAD CONVECTIVE COVERAGE. IT COULD COMPLETELY PROHIBIT ANY
STORMS FROM DEVELOPING ACROSS THE AREA THOUGH AGAIN THAT DEPENDS ON
WHERE THE WARM FRONT SETS UP. THIS UNCERTAINTY ALSO EXTENDS TO THE
LOCATION OF THE SURFACE LOW TIED TO THE WARM FRONT. LATEST ENSEMBLES
ARE IN LINE WITH THE LATEST HI-RES GUIDANCE IN LIFTING THE SURFACE
LOW THROUGH THE CENTER OF THE FORECAST AREA. THIS WOULD THEN TURN
SURFACE WINDS TO OUT OF THE WEST BOTH WITHIN AND BEHIND THE LOW. THE
WESTERLY WINDS WILL ADVECT MUCH DRIER AIR INTO THE AREA. THIS DRIER
AREA WILL MAKE FOR A MUCH NARROWER WARM SECTOR WITH THE BEST
INSTABILITY RESIDING JUST ALONG THE WARM FRONT ITSELF WHERE MOISTURE
IS STILL ABLE TO POOL. CAPE VALUES LOOK TO REACH UP TO 1500 TO 2000+
J/KG ALONG THE FRONT IN TANDEM WITH MORE THAN SUFFICIENT VERTICAL
SHEAR IN PLACE THANKS FOR AN UPPER LEVEL JET SITTING OVER THE AREA.
AS OF NOW, THE BEST CONVERGENCE ALONG THE WARM FRONT IS ALONG
HIGHWAY-14 FROM BROOKINGS, SOUTH DAKOTA TO MARSHALL, MINNESOTA. THIS
LOOKS TO BE THE MAIN AREA FOR CONVECTIVE DEVELOPMENT AS SUFFICIENT
LOW LEVEL MOISTENING AND CONVERGENCE LOOKS TO BE JUST ENOUGH TO
OVERCOME THE CAP. SHOULD STORMS DEVELOP, IT LOOKS TO BE A SMALLER
NUMBER OF STORMS, ONLY ABOUT 1 TO 3 STORMS. THUS, LARGE HAIL UP TO 2
INCHES IN DIAMETER, 70 MPH WINDS, AND AN ISOLATED TORNADO IS
POSSIBLE. THE MAIN TIMEFRAME FOR CONVECTION WOULD BE BETWEEN 3 PM TO
10 PM.
TUESDAY WILL BE A QUIETER DAY AS MONDAY'S BOUNDARY WILL BE PUSHED
OFF TO THE SOUTHEAST. THIS WILL KEEP ANY INSTABILITY ALONG WITH
STRONG TO SEVERE STORM CHANCES OUT OF THE AREA. HOWEVER, THERE
REMAINS THE POTENTIAL FOR SOME LIGHT RAIN IF A DEFORMATION ZONE CAN
SET UP. THOUGH IF IT DOES, ANY RAINFALL WOULD BE LIGHT AT A TENTH OF
AN INCH OR LESS. TUESDAY WILL ALSO BE SLIGHTLY COOLER WITH HIGH
TEMPERATURES IN THE UPPER 60S TO UPPER 70S.
CHANCES FOR STRONG TO SEVERE STORMS LOOK TO CONTINUE THROUGH THE
REST OF THE WEEK. WEDNESDAY COULD BE THE NEXT CHANCE FOR SEVERE
WEATHER AS MEDIUM RANGE GUIDANCE SHOWS ANOTHER WAVE PUSHING THROUGH
THE AREA. THESE MODELS DO SHOW THAT THIS WAVE MAY CLOSE OFF WHICH
COULD BRING A WARM FRONT FURTHER NORTH, THUS BRINGING MORE
INSTABILITY WITH IT. AS OF NOW, THE ENSEMBLES SHOW THE LOW STAYING
SOUTH AND EAST OF THE FORECAST AREA. WILL STILL KEEP AN EYE ON
TRENDS OVER THE COMING DAYS IN CASE THE LOW COMES NORTH. AS OF NOW,
HIGH TEMPERATURES LOOK TO WARM TO THE UPPER 60S TO LOW 70S.
THURSDAY LOOKS TO BE A QUIET DAY AS SHORTWAVE RIDGING PUSHES THROUGH
THE PLAINS. A STRONGER UPPER LEVEL WAVE LOOKS TO EJECT INTO THE
PLAINS ON FRIDAY. A STRONGER COLD FRONT WILL BE TIED TO THIS WAVE.
SEVERE STORMS COULD BE POSSIBLE ALONG THIS FRONT THOUGH CURRENTLY
MEDIUM RANGE GUIDANCE SHOWS THE COLD FRONT EITHER JUST ABOUT TO
FULLY PUSHING THROUGH THE FORECAST AREA BY FRIDAY EVENING. THIS
COULD PRECLUDE SEVERE WEATHER CHANCES IF THE FRONT PUSHES THROUGH
THE FORECAST AREA QUICKLY. SOMETHING TO KEEP AN EYE ON AS WE
PROGRESS THROUGH THE WEEK. CHANCES FOR PRECIPITATION COULD CONTINUE
THROUGH SATURDAY BEFORE DRY CONDITIONS RETURN FOR SUNDAY.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 639 AM CDT MON APR 13 2026
PLETHORA OF AVIATION CONCERNS THROUGH THE PERIOD WITH IFR AND
LOWER FOG THROUGH MID MORNING. ALSO, SHOWERS AND ISOLATED STORMS
CONTINUE TO MOVE EAST, MAINLY ACROSS SD THIS MORNING. ONCE FOG
LIFTS, SHOULD RETURN TO VFR CONDITIONS OUTSIDE OF ANY
SHOWERS/THUNDERSTORMS. SHRA/TSRA DEVELOP THIS AFTERNOON AND
CONTINUE THROUGH THE EVENING. STRONGEST STORMS - GREATEST RISK
ACROSS SOUTHWESTERN MN - MAY PRODUCE WIND GUSTS TO 60 KNOTS,
LARGE HAIL TO 2 INCHES, AND POSSIBLY A TORNADO. TIMING OF
GREATEST RISK WILL BE AFTER 21Z.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...SG
DISCUSSION...MEYERS
AVIATION...SG
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