264
FXUS63 KFSD 212352
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
652 PM CDT SAT JUN 21 2025
KEY MESSAGES
- THE DANGEROUS HEAT WILL CONTINUE THROUGH SUNDAY WITH
AFTERNOON/EVENING HEAT INDICES AVERAGING 100-110 DEGREES AND
NIGHT TIME INDICES ONLY FALLING TO 70-80 DEGREES. COOLER
CONDITIONS WILL RETURN TO CENTRAL SD BY SUNDAY AND THE REST OF
THE AREA BY SUNDAY NIGHT INTO MONDAY.
- BREEZY SOUTHERLY WINDS WILL CONTINUE THROUGH SUNDAY WITH
GUSTS BETWEEN 25-40 MPH AT TIMES. WHILE THE FIRE WEATHER
CONCERNS SHOULD BE KEPT TO A MINIMUM, LOCALLY ELEVATED
CONCERNS WILL BE POSSIBLE IN THE AREAS WHICH HAVE RECEIVED
LIMITED RAINFALL OVER THE PAST WEEK.
- THE RISK FOR SOME STRONGER STORMS RETURNS FROM SUNDAY EVENING
THROUGH MONDAY MORNING WITH THE PRIMARY RISKS BEING LARGE
HAIL AND STRONG WIND GUSTS. LOCALLY HEAVY DOWNPOURS WILL BE A
SECONDARY RISK.
- AN ACTIVE PATTERN ALOFT WILL CONTINUE FOR MUCH OF THE NEW
WEEK. WHILE SOME UNCERTAINTY REMAINS, A FAVORABLE SET UP ALOFT
WILL LEAD TO MULTIPLE CHANCES FOR SHOWERS AND THUNDERSTORMS
ALONG WITH LOCALLY HEAVY RAINFALL DURING THE MIDWEEK.
DISCUSSION
ISSUED AT 252 PM CDT SAT JUN 21 2025
CURRENTS & TONIGHT: ANOTHER HOT DAY CONTINUES! TAKING A LOOK ACROSS
THE AREA, THE MAIN FOCUS CONTINUES TO BE ON THE HEAT AS MOST AREAS
SIT IN THE LOW TO MID 90S WITH HEAT INDICES IN THE UPPER 90S TO LOW
100S AS OF 2 PM. THIS IS ALSO BEING ACCOMPANIED BY SOUTHERLY TO
SOUTHEASTERLY WINDS WITH GUSTS BETWEEN 20-45 MPH THIS AFTERNOON.
SIMILAR TO YESTERDAY, EXPECT A FEW SITES TO REACH THE LOW 100S FOR
HIGHS WITH HEAT INDICES BETWEEN 100 TO 110 DEGREES AT TIMES THROUGH
THIS EVENING WITH THE WARMEST CONDITIONS LIKELY OCCURRING ACROSS
PORTIONS OF THE MISSOURI RIVER VALLEY AND FAR SOUTHEASTERN SD. FROM
HERE, THE LOSS OF DIURNAL HEATING WILL HELP TEMPERATURES GRADUALLY
COOL INTO THE OVERNIGHT HOURS WITH LOWS LIKELY TOPPING OUT IN THE
MID TO UPPER 70S AND LOW 80S. WITH THIS IN MIND, WE'LL LIKELY HAVE
TO WATCH OUR TEMPERATURES THROUGH MIDNIGHT AS WE ARE ON TRACK TO SET
NEW RECORD WARM LOW TEMPERATURES AT KSUX (79) AND KMHE (75) TODAY.
LASTLY, WHILE THE POTENTIAL IS LOW (<30%); COULD SEE A FEW ELEVATED
SHOWERS DEVELOP ACROSS SOUTHCENTRAL SD LATE TONIGHT AS A SURFACE LOW
LIFTS ACROSS CENTRAL SD. WHILE THIS ACTIVITY IS NOT EXPECTED TO
BECOME SEVERE; CAN'T RULE OUT AN FEW HUNDREDTHS OF ACCUMULATION
WEST OF THE JAMES RIVER VALLEY.
SUNDAY: LOOKING INTO SUNDAY, ITS ANOTHER DAY OF RINSE AND REPEAT AS
WARM OVERNIGHT TEMPERATURES GRADUALLY INCREASE INTO THE LOW TO UPPER
90S AND LOWER 100S FOR THE DAY. WITH DEW POINTS EXPECTED TO ONCE
AGAIN BE IN THE 60S TO LOW 70S, EXPECT HEAT INDICES TO BE BETWEEN
THE 100 TO 110 DEGREE MARK FOR MOST AREAS EAST OF HIGHWAY-281. WHILE
THIS LIKELY PUTS US IN PRETTY GOOD SHAPE FOR OUR HEAT HEADLINES,
COULD SEE SOME TEMPERATURE CHANGES ON THE HORIZON AS A SURFACE LOW
LIFTS OUT OF NORTHEASTERN CO INTO WESTERN NE AND CENTRAL SD ALONG
WITH ITS SURFACE COLD FRONT. BY SUNDAY EVENING, MOST HIGH-RESOLUTION
GUIDANCE HAS SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP EITHER
ALONG OR JUST BEHIND THE 850MB FRONT MOSTLY WEST OF I-29. GIVEN THE
UNSTABLE AIRMASS AHEAD OF THE FRONT CHARACTERIZED BY 1000-1800 J/KG
OF INSTABILITY AND 35-45 OF BULK SHEAR, EXPECT DEVELOPING SEMI-
DISCRETE SUPERCELLS TO QUICKLY BECOME SEVERE WITH LARGE HAIL UP TO
GOLF BALL SIZE POSSIBLE INITIALLY AS LAPSE RATES STEEPEN TO 6-7
DEGREES C/KM.
AS DEVELOPING CONVECTION SHIFTS TOWARDS MORE MULTI-CELLULAR/CLUSTER
MODES DURING THE EVENING, WE'LL HAVE TO WATCH FOR STRONG WINDS GUSTS
UP TO 70 MPH AS DCAPE VALUES BETWEEN 1100-1500 J/KG AND DRIER AIR
ABOVE THE MIXED LAYER COULD LEAD TO STRONG COLD POOLS DEVELOPING
WITH STRONGEST ACTIVITY. WITH ALL THIS BEING SAID, STILL LOOKS LIKE
THE BETTER RISK FOR STRONGER STORMS SHOULD OCCUR BETWEEN 6 PM TO 1
AM WITH THE BETTER CHANCES ACROSS SOUTHEASTERN SD. AS THIS ACTIVITY
APPROACHES THE I-29 CORRIDOR BY SUNDAY NIGHT, SHOULD SEE THINGS
GRADUALLY WEAKEN WITH EASTWARD EXTENT AS INSTABILITY WANES WITH
TIME. LASTLY, A STRONG PUSH OF COLD AIR ADVECTION (CAA) BEHIND THE
SURFACE COLD FRONT SHOULD HELP TEMPERATURE DECREASE OVERNIGHT WITH
LOWS IN THE 60S TO LOW 70S EXPECTED ACROSS THE AREA.
MONDAY ONWARDS: HEADING INTO THE EXTENDED PERIOD, AN ACTIVE PATTERN
RETURN ALOFT AS SOUTHWESTERLY FLOW CONTINUES ON THE BACKSIDE OF THE
AFOREMENTIONED UPPER-LEVEL RIDGE. A LARGE-SCALE TROUGHING PATTERN
OVER THE WESTERN CONUS COUPLED WITH A PERSISTENT UPPER-LEVEL JET
STREAK WILL HELP FUEL OUR NEAR DAILY RAIN CHANCES OVER THE COURSE OF
THE WEEK AS MULTIPLE SHORTWAVES LIFT OUT OF THE ROCKIES INTO OUR
AREA. THE BETTER OF WHICH WILL LIKELY OCCUR BETWEEN TUESDAY AND
THURSDAY AS A STATIONARY BOUNDARY INTERACTS WITH SERIES OF WAVES
TRIGGER MULTIPLE ROUNDS OF SHOWERS AND POTENTIALLY THUNDERSTORMS.
WHILE THE SEVERITY OF THESE STORM IS STILL UNCERTAIN AT THIS TIME,
PWATS BETWEEN 1.00"-1.75" INCHES (TOP 1% OF CLIMATOLOGY) ALONG WITH
WARM CLOUD DEPTHS BETWEEN 10-12KT PRESENT A STRONG SIGNAL FOR
PERIODS OF LOCALLY HEAVY RAINFALL. COUPLE THIS WILL STORM MOTIONS
PARALLEL TO THE FRONT AND THE SET UP IS PRIMED FOR "TRAINING". WHILE
ITS STILL TO EARLY TO SAY EXACTLY WHERE THIS WILL OCCUR, CAN'T RULE
OUT THE POTENTIAL FOR SOME ISOLATED FLASH FLOODING IN THE AREAS THAT
RECEIVE THE MOST RAINFALL. SHOULD SEE QUIETER CONDITIONS RETURN TO
THE REGION BY FRIDAY AS WEEK MID-LEVEL RIDGE MOVES ACROSS THE AREA.
LASTLY, GIVEN THE INCREASING PRECIPITATION CHANCES; NEAR TO JUST
BELOW NORMAL TEMPERATURES WILL PERSIST FOR MOST OF THE WEEK WITH
DAILY HIGHS IN THE 70S AND 80S THOUGH FRIDAY.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 650 PM CDT SAT JUN 21 2025
VFR CONDITIONS EXPECTED THROUGH THIS TAF PERIOD. WE SHOULD BE MOSTLY
DRY THROUGH TOMORROW AFTERNOON; HOWEVER, AN ISOLATED SHOWER OR STORM
IS POSSIBLE LATE TONIGHT MAINLY WEST OF I-29. ANY SHOWER THAT
DEVELOPS IS CAPABLE OF A QUICK 40+KT WIND GUST, BUT WIDESPREAD
IMPACTS ARE NOT EXPECTED. FOR THIS REASON, ADDED A PROB30 GROUP
FROM 9-11Z FOR KHON. OTHERWISE, MAINLY CLEAR SKIES WILL PREVAIL
THROUGH THE PERIOD.
WINDS WILL STAY MOSTLY FROM THE SOUTHERLY DIRECTION, EXCEPT FOR THIS
EVENING WHEN NORTHWESTERLY WINDS ARE EXPECTED WEST OF THE JAMES
RIVER. WINDS IN THOSE AREAS WILL GRADUALLY TURN BACK TO THE
SOUTHEAST BY DAYBREAK. GUSTS WILL BE AS HIGH AS 30-35 KTS SUNDAY
AFTERNOON, STRONGEST ALONG AND EAST OF I-29. A COLD FRONT WILL MOVE
INTO THE AREA FROM CENTRAL SOUTH DAKOTA CLOSER TO THE END OF THE
PERIOD AND START TO TURN WINDS MORE WESTERLY FOR THOSE WEST OF THE
JAMES. LLWS CONCERNS WILL CONTINUE FOR KFSD AND KSUX TONIGHT AS
WINDS KICK UP TO AROUND 50 KTS AT ABOUT 1500 FT.
FSD WATCHES/WARNINGS/ADVISORIES
SD...EXTREME HEAT WARNING UNTIL 9 PM CDT SUNDAY FOR SDZ061-062-
065>071.
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR SDZ038-050-052-
053-057>059-063-064.
HEAT ADVISORY UNTIL 6 PM CDT SUNDAY FOR SDZ039-040-054>056-060.
MN...EXTREME HEAT WARNING UNTIL 9 PM CDT SUNDAY FOR MNZ071-072-080-
081-089-090-097-098.
IA...EXTREME HEAT WARNING UNTIL 9 PM CDT SUNDAY FOR IAZ001>003-
012>014-020>022-031-032.
NE...EXTREME HEAT WARNING UNTIL 9 PM CDT SUNDAY FOR NEZ013-014.
DISCUSSION...05
AVIATION...SAMET
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