018
FXUS63 KFSD 060918
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
318 AM CST THU MAR 6 2025
KEY MESSAGES
- A PLEASANT DAY TODAY, THOUGH CLOUDS WILL BE INCREASING AHEAD
OF THE NEXT SYSTEM THAT WILL BRING PRECIPITATION TO OUR
MISSOURI RIVER COUNTIES.
- PRECIPITATION IS EXPECTED TO BEGIN THIS AFTERNOON OVER SOUTH
CENTRAL SOUTH DAKOTA AND MOVE EAST. PRECIPITATION WILL BEGIN
AS RAIN BUT QUICKLY CHANGE OVER TO SNOW. CHANCES FOR SNOW LOOK
TO BE MAINLY CONFINED TO THE MISSOURI RIVER VALLEY WHERE WE
ARE EXPECTING AROUND 2-5 INCHES WITH POCKETS OF HIGHER AMOUNTS
POSSIBLE. A WINTER WEATHER ADVISORY IS IN EFFECT BEGINNING
THIS EVENING AND CONTINUING THROUGH FRIDAY EVENING.
- SNOW TAPERS OFF FRIDAY EVENING. WEEKEND TEMPERATURES LOOK TO
BE WELL ABOVE AVERAGE AND PERSIST INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 312 AM CST THU MAR 6 2025
THIS MORNING: LOOKING AT SATELLITE WE SEE CLOUDS DRIFTING IN FROM
THE WEST ASSOCIATED WITH THE LOW PRESSURES SYSTEM SITUATED OVER
THE CENTRAL ROCKIES. THESE CLOUDS WILL CONTINUE TO FILL IN
THROUGH THE DAY TODAY AS THE AIR MASS ALOFT SATURATES FROM THE
TOP DOWN. WAA AHEAD OF THE APPROACHING SYSTEM WILL BOOST OUR
AFTERNOON HIGHS INTO THE 40S ACROSS THE REGION. LIGHT SOUTHERLY
WINDS WILL BECOME NORTHERLY THEN NORTHEASTERLY, AND INCREASE TO
5-10 MPH.
THIS EVENING AND FRIDAY: THE AFOREMENTIONED LOW PRESSURE SYSTEM WILL
EJECT OUT OVER THE CENTRAL PLAINS, AND PASS JUST SOUTH OF OUR AREA.
MODEL SOUNDINGS INDICATE STRONG OMEGA IN THE DGZ AND WEAK
INSTABILITY. THIS COUPLED WITH STRONG FRONTOGENESIS IN THE 700-600
MB LAYER WILL ALL WORK TOGETHER TO SUPPORT THE FORMATION OF A
HEAVIER BAND OF PRECIPITATION. INITIALLY, TEMPERATURES IN THE
BOUNDARY LAYER SHOULD BE WARM ENOUGH THAT PRECIPITATION WILL BE
RAIN. HOWEVER, THE LAYER QUICKLY COOLS TO BELOW FREEZING, WITH A
RAPID CHANGEOVER TO SNOW FOLLOWING. QPF WITH THIS SYSTEM IS IN THE
90TH PERCENTILE FOR CLIMATOLOGY, WITH AREAS ALONG THE MISSOURI RIVER
AND SOUTH SITTING AT 0.4-0.75 INCHES OF LIQUID EQUIVALENT. SLR RANGE
FROM AROUND 8:1 AT ABOUT THE TIME SNOW IS EXPECTED TO BEGIN FALLING,
TO AROUND 13:1 FOR A BRIEF WINDOW AT ITS PEAK. AT THE SURFACE, THIS
WILL LOOK LIKE TOTALS BETWEEN 2-5 INCHES, WITH ISOLATED POCKETS OF 6
POSSIBLE. THIS MATCHES WELL WITH ENSEMBLE 25TH AND 75TH
PERCENTILE RANGES. WINDS WILL BE NORTHEASTERLY THURSDAY NIGHT
AROUND 5 MPH, BECOMING NORTHERLY AND INCREASING TO AROUND 10 MPH
BY MID-DAY FRIDAY. GUSTS ARE EXPECTED TO INCREASE DURING THIS
TIME AS WELL TO AROUND 15-20 MPH. WHILE THESE ARE GENERALLY NOT
CONSIDERED STRONG WINDS, THEY WILL BE AT THEIR PEAK DURING THE
PEAK TIMEFRAME OF SNOWFALL. SOME BRIEF REDUCTIONS IN VISIBILITY
COULD RESULT. CONSIDERING THE TOTALS WE ARE ESTIMATING AND THE
WINDS, HAVE DECIDED TO GO WITH A WINTER WEATHER ADVISORY FOR THE
COUNTIES ALONG THE MISSOURI RIVER VALLEY, AND EAST INTO
NORTHWESTERN IOWA FROM THURSDAY EVENING UNTIL FRIDAY EVENING.
ALONG HERE AND SOUTH IS WHERE THE HEAVIEST BAND OF SNOW IS
EXPECTED TO SET UP. NORTH OF HERE THE TOTALS FALL OFF QUICKLY TO
AROUND I-90 WHERE FLURRIES TO A HALF AN INCH ARE POSSIBLE.
SHIFTS NORTH OR SOUTH IN TRACK COULD HAVE AN INFLUENCE ON TOTALS
AND EXACTLY WHERE THE HEAVIER BAND SETS UP.
THE WEEKEND AND NEXT WEEK: SNOW CLEARS OUT FRIDAY NIGHT, AND CLOUDS
DECREASE AS AN UPPER RIDGE BUILDS IN. A VERY PLEASANT FORECAST FOR
THIS WEEKEND WITH MOSTLY SUNNY SKIES AND HIGHS IN THE 40S AND 50S
SATURDAY, AND 50S AND 60S FOR SUNDAY. WINDS WILL BE BREEZY EACH
AFTERNOON.
FLOW ALOFT BECOMES QUASI-ZONAL FOR THE FIRST HALF OF THE WEEK. DRY
CONDITIONS WILL PREVAIL WITH CONTINUED WARM HIGH TEMPERATURES. HIGHS
MONDAY WILL BE WIDESPREAD UPPER 50S AND 60S, ABOUT 20 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR. WHILE NO RECORD HIGHS LOOK TO BE IN
DANGER OF BREAKING, WE COULD GET WITHIN FEW DEGREES OF THEM IN
PLACES. TUESDAY COOLS DOWN A LITTLE AFTER A COLD FRONT MOVES THROUGH
THE REGION, HIGHS WILL REACH THE 50S. CONTINUED NORTHEASTERLY
FLOW AND CAA WILL LIMIT HIGHS FOR WEDNESDAY TO THE 40S AND 50S.
BY THURSDAY, WE BEGIN TO SEE SIGNALS FOR ANOTHER STRONG LOW
PRESSURE SYSTEM. BUT THIS FAR OUT THERE IS TOO MUCH UNCERTAINTY
FOR SPECULATION ON DETAILS.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1028 PM CST WED MAR 5 2025
VFR CONDITIONS THROUGH THE NIGHT AND INTO THURSDAY. BY LATE
AFTERNOON RAIN WILL BE POSSIBLE NEAR THE MISSOURI RIVER, WHICH
WILL THEN LIFT NORTH AND EAST TO BETWEEN I-90 AND THE MISSOURI
RIVER BETWEEN 0-6Z FRIDAY. THE RAIN SHOULD THEN CHANGE TO SNOW
WITH MVFR AND POSSIBLY IFR CONDITIONS DEVELOPING. A HIGHER
CHANCE FOR IFR AND POSSIBLY LIFR CONDITIONS IN SNOW NEAR THE
MISSOURI RIVER AFTER 6Z FRIDAY WHICH WILL LIKELY CONTINUE
THROUGH FRIDAY MORNING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR SDZ050-063-068>071.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR IAZ020>022-031-032.
NE...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST
FRIDAY FOR NEZ013-014.
DISCUSSION...AJP
AVIATION...08
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