431
FXUS63 KFSD 060534
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1234 AM CDT WED MAY 6 2026
KEY MESSAGES
- AREAS OF FROST ARE EXPECTED TONIGHT ESPECIALLY NORTH OF I-90.
BOTH A FREEZE WARNING AND FROST ADVISORY WILL BE IN EFFECT
FROM 1 AM THROUGH 7 AM CDT FOR PORTIONS OF THE AREA. MAKE
SURE TO COVER/BRING IN ANY SENSITIVE VEGETATION!
- ADDITIONAL AREAS OF FROST WILL BE POSSIBLE BY THURSDAY
MORNING. HOWEVER, SLIGHTLY LESS COLD TEMPERATURES AND HIGHER
DEW POINT DEPRESSION MAY LIMIT COVERAGE/EXTENT.
- AFTER BELOW NORMAL TEMPERATURES THROUGH WEDNESDAY, NEAR TO
ABOVE NORMAL TEMPERATURES WILL CONTINUE INTO THE WEEKEND WITH
HIGHS MAINLY IN THE 60S TO 70S.
UPDATE
ISSUED AT 841 PM CDT TUE MAY 5 2026
THE FORECAST REMAINS ON TRACK THIS EVENING WITH HIGH PROBABILITY
(>80%) FOR FREEZING CONDITIONS FOR AREAS ALONG AND NORTH OF I-90 IN
SOUTHEAST SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THE FREEZE WARNING
IN THIS AREA FROM 1 AM UNTIL 7 AM WEDNESDAY MORNING IS IN GOOD SHAPE
AND NO ADJUSTMENTS HAVE BEEN MADE. AREAS TO THE SOUTH OF I-90 THERE
REMAINS A LITTLE UNCERTAINTY AS SOUNDINGS INDICATE MID TO UPPER
LEVEL CLOUDS HANGING AROUND THROUGH AT LEAST THE FIRST HALF OF THE
OVERNIGHT. IF THEY LINGER LONGER THEY COULD SLOW OR PREVENT SURFACE
TEMPERATURES FROM REACHING FREEZING. IN ADDITION, LARGE DEW POINT
DEPRESSIONS OF 10-12 DEGREES F WILL LIKELY PREVENT FROST FROM
FORMING AT ALL. HOWEVER, THE PROJECTED LOW TEMPERATURES OF 29-32
DEGREES F COULD STILL CAUSE DAMAGE TO SENSITIVE VEGETATION. FOR
THESE REASONS, HAVE DECIDED TO EXPANDED THE FROST ADVISORY TO
INCLUDE GREGORY, CHARLES MIX, BON HOMME, AND YANKTON COUNTIES IN
THE EXISTING ADVISORY FROM 1 AM UNTIL 7 AM WEDNESDAY MORNING.
TEMPERATURES RAPIDLY INCREASE AFTER SUNRISE REACHING HIGHS OF
LOW TO MID 50S, AROUND 10 DEGREES BELOW AVERAGE FOR THIS TIME OF
YEAR (MID 60S).
DISCUSSION
ISSUED AT 120 PM CDT TUE MAY 5 2026
CURRENTS & TONIGHT: ANOTHER MILD AND BREEZY DAY CONTINUES! TAKING A
LOOK ACROSS THE AREA THIS AFTERNOON, CLOUD COVER CONTINUES TO FILTER
IN AS BREEZY NORTHWESTERLY WINDS PERSISTS WITH GUSTS BETWEEN 20-30
MPH. WHILE DRIER CONDITIONS THIS AFTERNOON COULD PROMOTE SOME
LOCALLY ELEVATED FIRE CONCERNS, GREENER FUELS AND MILDER
TEMPERATURES WILL LIKELY KEEP ANY FIRE DANGER RISK IN THE LOW TO
MODERATE CATEGORIES. OTHERWISE, THE MAIN CONCERN TONIGHT CONTINUES
TO BE THE POTENTIAL FOR FROST/FREEZE CONDITIONS. WITH THE RETURN OF
NEAR TO SUB-FREEZING TEMPERATURES (26-32 DEGREES) AND LIGHTER
SURFACE WINDS TONIGHT, AREAS OF FROST ARE EXPECTED TO DEVELOP ACROSS
MOST AREAS ESPECIALLY ALONG AND NORTH OF I-90. WHILE THERE IS
STILL SOME UNCERTAINTY WITH COVERAGE MAINLY DUE TO 5-10 DEGREE
DEW POINT DEPRESSION, STILL THINKING THE CONDITIONS WILL DO JUST
ENOUGH FOR SENSITIVE PLANTS TO BE AFFECTED. AS A RESULT, HAVE
COLLABORATED WITH NEIGHBORING OFFICES TO ISSUE BOTH A FREEZE
WARNING AND FROST ADVISORY FROM 1 AM TO 7 AM CDT. MY THOUGHTS
ARE THE WARNING IS IN PLACE WHERE CONFIDENCE IS HIGHEST ON SUB-
FREEZING TEMPERATURES AND WIDESPREAD DEVELOPMENT WITH SMALL DEW
POINT DEPRESSIONS. THE ADVISORY IS IN PLACE FOR AREAS WHERE
PATCHY TO SCATTERED AREAS OF FROST ARE POSSIBLE. WITH ALL THIS
IN MIND, MAKE SURE TO COVER/BRING IN ANY SENSITIVE VEGETATION!
WEDNESDAY-THURSDAY: LOOKING INTO THE MIDWEEK, LINGERING COLD AIR
ADVECTION (CAA) AND NORTHWESTERLY SURFACE WINDS WILL KEEP THE MILDER
STRETCH GOING THROUGH AT LEAST WEDNESDAY NIGHT WITH HIGHS IN THE LOW
TO UPPER 50S AND OVERNIGHT LOWS IN THE LOW TO MID 30S. SIMILAR TO
TONIGHT, WE COULD SEE ADDITIONAL CHANCES FOR FROST BY THURSDAY
MORNING. HOWEVER, BORDER-LINE TEMPERATURES AND A HIGHER DEW POINT
DEPRESSION (8-12 DEGREES) WILL LIKELY MAKE COVERAGE MORE PATCHY THAN
SCATTERED WITH THE MAIN FOCUS BEING ALONG OUR RIVER VALLEYS. BY
THURSDAY, WE'LL START TO TREND WARMER AS A WEAKENING RIDGE AND A
RETURN TO SOUTHWESTERLY TO WESTERLY FLOW BRINGS AN INFLUX OF WARMER
AIR TO THE AREA. THIS WILL LEAD TO BEAUTIFUL CONDITIONS AS HIGHS
PEAK IN THE 60S TO LOW 70S FOR THE DAY WITH LIGHTER WINDS.
THE WEEKEND ONWARDS: HEADING INTO THE EXTENDED PERIOD, AN ACTIVE
PATTERN WILL ONCE AGAIN RETURN AS CONTINUOUS NORTHWESTERLY FLOW
ALOFT HELPS USHER IN MULTIPLE WAVES THROUGH OUR AREA. THE STRONGEST
OF WHICH LOOKS TO ARRIVE BETWEEN SATURDAY TO SUNDAY. WHILE THERE IS
STILL SOME VARIABILITY AMONG LONG-RANGE GUIDANCE, THIS STILL LOOKS
LIKE OUR BEST CHANCES (20%-30%) FOR AREAS ALONG AND SOUTH OF I-90 TO
SEE RAIN. THIS IS FURTHER AGREED UPON WITHIN ENSEMBLE GUIDANCE WITH
MOST MEMBERS SHOWING A 30%-60% CHANCE FOR AT LEAST MEASURABLE
PRECIPITATION. LASTLY, WE'LL CONTINUE OUR WARMING TREND THROUGH
MONDAY WITH HIGHS MAINLY IN THE 60S TO LOW 70S.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1233 AM CDT WED MAY 6 2026
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THIS PERIOD. MID TO HIGH
LEVEL CLOUDS WILL ALSO PREVAIL WITH A PERIOD OF LOWER CEILINGS MID
MORNING TO EARLY AFTERNOON AROUND 5000 FT AGL. CEILINGS IMPROVE AS
CLOUDS CLEAR OUT IN THE LATE AFTERNOON.
OVERNIGHT WINDS WILL BE LIGHT AND VARIABLE. AFTER SUNRISE WINDS
BECOME NORTHWESTERLY AND GRADUALLY INCREASE. AFTERNOON GUSTS OF 17-
22 KTS WILL BE WIDESPREAD ACROSS THE REGION. WINDS DECREASE AFTER
SUNSET BECOMING LIGHT AND VARIABLE NEAR THE END OF THE PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR SDZ050-063>071.
FREEZE WARNING UNTIL 7 AM CDT THIS MORNING FOR SDZ038>040-
052>062.
MN...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR MNZ090.
FREEZE WARNING UNTIL 7 AM CDT THIS MORNING FOR MNZ071-072-080-
081-089-097-098.
IA...FROST ADVISORY UNTIL 7 AM CDT THIS MORNING FOR IAZ001>003-
012>014-020>022.
NE...NONE.
UPDATE...AJP
DISCUSSION...05
AVIATION...AJP
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