045
FXUS63 KFSD 180914
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
414 AM CDT SAT JUL 18 2026
KEY MESSAGES
- AFTER A BRIEF REPRIEVE TODAY, HOTTER CONDITIONS RESUME ON
SUNDAY AND LIKELY MONDAY WHERE HEAT INDICES COULD CLIMB INTO
THE LOW 100S.
- VERY PATCHY MORNING VALLEY FOG WILL BE POSSIBLE DAILY, BUT
WIDESPREAD DENSE FOG REMAINS UNLIKELY. FOG COULD REDUCE
VISIBILITY BELOW TWO MILES AT TIMES.
- WILDFIRE SMOKE RETURNS TODAY. TEMPORARY REDUCTIONS IN
VISIBILTY WILL BE POSSIBLE THROUGH SUNDAY ESPECIALLY ACROSS
SOUTHWESTERN MN. ANY SENSITIVE GROUPS SHOULD BEGIN TO MONITOR
THEIR LOCAL AIR QUALITY.
- PRECIPITATION IS VERY UNLIKELY (LESS THAN 20%) THROUGH SUNDAY.
ISOLATED TO SCATTERED SHOWER AND STORM CHANCES RETURN SUNDAY
EVENING AND NIGHT, BUT CONFIDENCE IS LOW ON DETAILS.
UPDATE
ISSUED AT 408 AM CDT SAT JUL 18 2026
TAKING A LOOK ACROSS THE AREA, THE FOCUS CONTINUES TO BE ON THE
WILDFIRE SMOKE THIS MORNING. IN THE WAKE OF THIS MORNING'S SURFACE
COLD FRONT, IT SEEMS LIKE SOME HIGHER SMOKE CONCENTRATIONS ARE BEING
PULLED DOWN TO THE SURFACE LEADING TO SLIGHT VISIBILITY REDUCTIONS
BEING OBSERVING ACROSS PARTS OF THE AREA. WHILE THIS HAS MOSTLY
AFFECTING OUR HIGHER ELEVATION AREAS NORTH OF I-90, COULD SEE
ADDITIONAL VISIBILITY REDUCTIONS ALONG AND EAST OF I-29 THROUGHOUT
THE DAY. WITH THE AIR QUALITY INDEX (AQI) CITING MODERATE TO
UNHEALTHY CONCENTRATIONS OF SMOKE, MAKE SURE TO PAY ATTENTION TO
YOUR LOCAL FORECAST ESPECIALLY IF YOU'RE APART OF A SENSITIVE GROUP.
OTHERWISE, ITS GONNA BE A NICE SUMMER DAY WITH HIGHS MAINLY IN THE
MID 80S TO MID 90S. SURFACE WINDS WILL REMAIN MOSTLY LIGHT AND TURN
TO THE NORTHEAST BEHIND THE PREVIOUSLY MENTIONED FRONT. LASTLY,
COULD SEE A FEW SCATTERED SHOWERS TO ISOLATED THUNDERSTORMS DEVELOP
ALONG AND SOUTH OF THE HIGHWAY-20 CORRIDOR THIS AFTERNOON WITH THE
SOUTHWARD PROPAGATING FRONT. WHILE SEVERE WEATHER IS NOT EXPECTED,
AN OCCASIONAL STROKE OF LIGHTNING AND POCKETS OF MODERATE TO HEAVY
RAINFALL WILL BE POSSIBLE IF THINGS CAN DEVELOP.
DISCUSSION
ISSUED AT 1251 PM CDT FRI JUL 17 2026
A WEAK COOL FRONT WILL SAG SOUTH TONIGHT INTO SATURDAY. MOISTURE
AND FORCING ALONG THIS BOUNDARY ARE VERY WEAK, SO SHOWERS AND STORMS
ARE VERY UNLIKELY. PARTS OF NORTHWEST IA LATE THIS AFTERNOON COULD
SEE A SPOTTY SHOWER OR STORM AS A FEW OF THE MODELS INDICATE A
WEAKENING CAP, BUT WITH NO SHEAR AND ABOUT 500 J/KG OF SKINNY CAPE,
BRIEF HEAVY RAIN SHOULD BE THE ONLY CONCERN.
OTHERWISE SATURDAY SHOULD SEE A BIT OF A REPRIEVE FROM THE HEAT FOR
MANY WITH HIGHS EXPECTED TO RANGE FROM THE MID 80S IN SOUTHWEST MN
TO THE MID 90S ALONG THE MISSOURI RIVER. ONE CONCERN ON SATURDAY
WILL BE THE POTENTIAL FOR SOME SURFACE BASED SMOKE FROM THE FIRES
ACROSS NORTHERN MN. WITH WINDS TURNING NORTH AND THEN NORTHEAST,
SOME OF THIS COULD LEAK INTO THE AREA. FOR NOW SMOKE CONCENTRATION
LOOK TO REMAIN FAIRLY LOW.
SUNDAY WILL SEE A RETURN OF SOUTHERLY FLOW AND HOTTER CONDITIONS AS
UPPER LEVEL RIDGING BUILDS AHEAD OF A STRENGTHENING JET ALONG THE
CANADIAN BORDER NEAR MT. STILL SOME HINTS OF ELEVATED MOISTURE AND
VERY WEAK INSTABILITY L;ATE SATURDAY NIGHT INTO SUNDAY MORNING WHICH
COULD LEAD TO ISOLATED SHOWERS AND A VERY ISOLATED THUNDERSTORM.
HOWEVER, THE LATEST MODEL RUNS ARE DRIER ALOFT THAN PREVIOUS RUNS,
SO CONFIDENCE IN THIS IS WANING. OTHERWISE, MAY NEED A HEAT ADVISORY
FOR AREAS NEAR AND WEST OF I-29 SUNDAY AFTERNOON AND EVENING WITH
HEAT INDICES LIKELY ABOVE 100. SUNDAY NIGHT WILL SEE FAIRLY STRONG
SOUTHERLY FLOW IN PLACE WHICH WILL LEAD TO VERY WARM LOWS IN THE 70S.
MONDAY STILL HAS A FEW QUESTION MARKS ON HEAT, BUT FOR AREAS NEAR
AND SOUTH OF I-90 THERE WILL AGAIN BE A VERY GOOD CHANCE FOR HEAT
INDICES OF 100 OR GREATER. THIS IS DUE TO THAT JET MAX TO THE
NORTHWEST NOW DIVING SOUTHEAST INTO THE AREA AND DRAGGING SOME
COOLER AIR SOUTH. FOR NOW COVERAGE OF ANY SHOWERS AND THUNDERSTORMS
LOOKS ISOLATED TO SCATTERED WITH THE BETTER CHANCES SUNDAY NIGHT
INTO MONDAY EVENING. FRONTAL TIMING AND MID LEVEL MOISTURE WILL PLAY
A BOG ROLE ON COVERAGE.
ONCE THIS FRONT SAGS SOUTH MONDAY EVENING, STRONGER NORTHWEST FLOW
ALOFT WILL REMAIN IN PLACE WHICH WILL BRING TEMPERATURES BACK TO
NORMAL OR A BIT BELOW NORMAL FOR THE REMAINDER OF THE WEEK. WHILE
THERE WILL LIKELY BE A COUPLE OF WEAKER WAVES DURING THIS TIME
CONFIDENCE ON ANYTHING MORE THAN ISOLATED IS LOW.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1053 PM CDT FRI JUL 17 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE PERIOD. WINDS ARE
LIGHT BECOMING NORTHERLY AND LIGHT BEHIND A COLD FRONT AS IT WORKS
ITS WAY THROUGH THE REGION TONIGHT. SKIES WILL BE CLEAR TO SCATTERED
HIGH LEVEL CLOUDS.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
UPDATE...05
DISCUSSION...08
AVIATION...AJP
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