764
FXUS63 KFSD 300849
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
249 AM CST THU JAN 30 2025
KEY MESSAGES
- TODAY WILL BE ANOTHER WARM DAY WITH HIGHS IN THE 50S. MILD
TEMPERATURES WILL CONTINUE INTO THIS WEEKEND, AND THEN COOL
FOR NEXT WEEK.
- LOW (10-30%) CHANCE OF RAIN FOR AREAS ALONG AND SOUTH OF
HIGHWAY 20 THIS AFTERNOON AND EVENING. HIGH (90+%)
PROBABILITY THAT RAINFALL, IF IT OCCURS, REMAINS LESS THAN
0.10 INCH.
- A MORE UNSETTLED PATTERN RETURNS SUNDAY NIGHT THROUGH THE END
OF THE WEEK, THOUGH NO SIGNIFICANT STORM SYSTEMS ARE
EXPECTED.
DISCUSSION
ISSUED AT 247 AM CST THU JAN 30 2025
THIS MORNING-TODAY: LOOKING AT GOES NIGHTTIME MICROPHYSICS WE CAN
SEE SOME HIGH CIRRUS CLOUDS TO OUR NORTH FLOWING EAST-SOUTHEAST. TO
THE SOUTH WE CAN SEE AN ADVANCING LOW PRESSURE SYSTEM THAT MAY BE
BRING SOME LIGHT PRECIPITATION TO OUR SOUTHERN COUNTIES THURSDAY
EVENING INTO EARLY FRIDAY MORNING.
MODELS ARE IN FAIR AGREEMENT ON THE TRACK OF THE LARGE LOW PRESSURE
SYSTEM AS IT MOVES FROM TEXAS NORTHEAST INTO KANSAS THEN IOWA THIS
AFTERNOON. DETERMINISTIC GUIDANCE HAS PRECIPITATION FORMING
ALONG PERIPHERY VORTICITY BANDS ALONG THE NORTH-NORTHWEST SIDE
OF THE SURFACE LOW AND PUSHING NORTH INTO OUR NORTHEASTERN
NEBRASKA, EXTREME SOUTHEASTERN SOUTH DAKOTA, AND NORTHWESTERN
IOWA COUNTIES. PRECIPITATION LOOKS TO REMAIN ALONG AND SOUTH OF
HIGHWAY 20, AND MOSTLY EAST OF SIOUX CITY. ENSEMBLE GUIDANCE
HAS HELD STEADY WITH A 10-30% PROBABILITY FOR MEASURABLE (0.01
LIQUID EQUIVALENT) PRECIPITATION. THE AREA MOST LIKELY TO SEE
ANY PRECIPITATION IS SOUTH OF A LINE FROM SIOUX CITY TO STORM
LAKE. MODEL SOUNDINGS INDICATE A MODERATELY DRY SUBCLOUD LAYER,
THAT MAY WORK TO FURTHER LIMIT HOW MUCH PRECIPITATION ACTUALLY
REACHES THE GROUND. ANALYSIS OF TEMPERATURE PROFILES INDICATE
THAT ANY PRECIPITATION THAT DOES FALL SHOULD BE IN THE FORM OF
RAIN. TOTALS ARE EXPECTED TO BE A TRACE TO 0.1". WHILE IT WILL
BE LIQUID AS IT FALLS, OVERNIGHT LOW TEMPERATURES ARE EXPECTED
TO FALL BELOW FREEZING, SO WET PAVEMENT AND ROADWAYS MAY FREEZE
AND BECOME SLIPPERY. AFTERNOON HIGHS ARE EXPECTED TO BE
UNSEASONABLY WARM, IN THE 50S FOR MOST OF THE REGION. LOWS WILL
BE IN THE 20S.
FRIDAY: AS THE SURFACE LOW MOVES OFF TO THE EAST, A SECONDARY LOW
PRESSURE DRAGS A WEAK COLD FRONT THROUGH THE REGION, TURNING WINDS
FROM SOUTHERLY TO NORTHERLY BY LATE THURSDAY, EARLY FRIDAY MORNING.
ALOFT, A WEAK RIDGE BUILDS INTO THE AREA AS A SURFACE HIGH OVER
SASKATCHEWAN SINKS SOUTH. CAA IN THE 925-850 MB LAYER WILL COOL
TEMPERATURES THERE INTO THE 0 TO -4 C RANGE. AT THE SURFACE WE CAN
EXPECT HIGHS TO REACH THE MID 30S TO 40S.
SATURDAY: AS THE EVENING APPROACHES, THE SURFACE HIGH MOVES EAST AND
THE UPPER LEVEL FLOW BECOMES ZONAL. WINDS AT THE SURFACE BECOME
EASTERLY, THEN SOUTHEASTERLY. SOME MID-RANGE DETERMINISTIC GUIDANCE
HAS LIGHT PRECIPITATION FORMING IN THE WARM SECTOR OF A QUICK MOVING
SURFACE LOW APPROACHING FROM WYOMING SATURDAY MORNING. ENSEMBLES
INDICATE A VERY LOW PROBABILITY (<20%) OF MEASURABLE PRECIPITATION
FALLING FOR AREAS ALONG AND NORTH OF I-90, WITH THE AREA MOST LIKELY
TO SEE PRECIPITATION EAST OF I-29 AND NORTH OF I-90 IN SOUTHWESTERN
MINNESOTA. THERMAL PROFILES INDICATE THAT THIS PRECIPITATION WILL
MOST LIKELY FALL IN THE FORM OF LIGHT SNOW. SOME MINOR TRAVEL
IMPACTS ARE POSSIBLE HERE, SO BE SURE YOU CONTINUE TO MONITOR THE
FORECAST FOR UPDATES. A STRONG PUSH OF WAA WILL BOOST AFTERNOON
TEMPERATURES TO WELL ABOVE AVERAGE ONCE AGAIN, IN THE MID 40S NORTH
OF I-90, AND 50S SOUTH.
SUNDAY: ZONAL FLOW ALOFT AND SOUTHEASTERLY WINDS AT THE SURFACE
CONTINUE FOR SUNDAY. HIGHS ARE EXPECTED TO REMAIN MILD, BUT COOLER
THAN SATURDAY, IN THE 40S. THIS IS LIKELY TO BE OUR LAST MILD DAY
THROUGH AT LEAST MID NEXT WEEK. MEANWHILE, A TROUGH DEVELOPS OVER
THE CENTRAL CANADIAN ROCKIES AND MAKES ITS WAY EAST, DRAGGING A COLD
FRONT ALONG WITH IT. A MIDLEVEL SHORTWAVE COULD TRIGGER ANOTHER
ROUND OF PRECIPITATION SUNDAY, THAT MAY BEGIN AS RAIN AND TRANSITION
TO SNOW. DETAILS ARE LACKING AT THIS POINT, AND SO CONFIDENCE IN
TRACK IS LOW. AS WE CONTINUE INTO NEXT WEEK, HIGHS WILL COOL TO
AROUND SEASONABLE, THEN SLIGHTLY COOLER THAN SEASONABLE, IN THE 20S,
THEN TEENS. PERIODIC PRECIPITATION, MOST LIKELY IN THE FORM OF SNOW,
IS POSSIBLE AS ADDITIONAL IMPULSES MAKE THEIR WAY THROUGH THE ZONAL
PATTERN.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1042 PM CST WED JAN 29 2025
VFR CONDITIONS CONTINUE THROUGH THURSDAY NIGHT. SOME WIND GUSTS
THROUGH 30.12Z OF AROUND 20 KNOTS ARE POSSIBLE FOR HIGHER
ELEVATION AREAS; OTHERWISE, SUSTAINED WINDS AROUND 10 KNOTS OR
SO ARE EXPECTED THROUGH THE PERIOD. SOUTHERLY WINDS SHIFT TO
NORTHWESTERLY BY THE AFTERNOON HOURS, BECOMING MORE NORTHERLY BY
31.00Z. SOUTHWESTERLY TO WESTERLY LLJ TONIGHT ALONG AND NORTH
OF I-90 WILL LEAD TO LLWS THROUGH 30.12Z ACROSS THE AREA. THE
GREATEST IMPACTS WILL BE ALONG AND NORTH OF I-90 WITH MORE
MARGINAL SPEED SHEAR FOR KSUX AND ADJACENT AREAS. ADDED MENTION
TO THIS FORECAST FOR KSUX.
A STORM SYSTEM PASSING WELL TO OUR SOUTH LEADS TO INCREASING
MID/LOWER LEVEL CLOUDS FOR THE US HWY 20 CORRIDOR INTO THE US
HWY 18 CORRIDOR DURING THE DAY ON THURSDAY; ISOLATED MVFR
CEILINGS ARE POSSIBLE BUT UNLIKELY (LESS THAN 30%). ISOLATED
SHOWERS MAY OCCUR AROUND/AFTER 30.21Z IN THIS AREA, BUT WITH
LOWER CONFIDENCE IN COVERAGE, WILL CONTINUE TO OMIT FROM KSUX
FOR NOW. BETTER CHANCES FOR PRECIPITATION AND MVFR CEILINGS
EXIST TO THE SOUTH AND EAST OF A KSUX TO KCKP LINE.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...AJP
AVIATION...SG
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