179
FXUS63 KFSD 011704
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1104 AM CST SAT MAR 1 2025
KEY MESSAGES
- TEMPERATURES TURN COOLER TODAY, THOUGH MAINLY ABOVE TO AROUND
NORMAL TEMPERATURES ARE EXPECTED SUNDAY THROUGH NEXT WEEK
WITH WEDNESDAY BEING THE NEXT COOLER DAY.
- A MAJOR STORM SYSTEM MOVES ONTO THE CENTRAL PLAINS TUESDAY.
STILL UNCERTAINTY, BUT SOME MODERATE IMPACTS WILL BE POSSIBLE
IF ENOUGH COLD AIR CAN GET INTO THE BACKSIDE OF THE SYSTEM TO
PRODUCE SNOWFALL. ALSO SOME POTENTIAL FOR HIGHER RAINFALL
AMOUNTS, ESPECIALLY OVER NORTHWEST IA WITH A 30-50%
PROBABILITY OF AT LEAST 0.50".
- STRONG NORTHERLY WINDS WILL BE POSSIBLE TUESDAY NIGHT INTO
WEDNESDAY NEXT WEEK DEPENDING UPON THE TRACK OF THE SYSTEM.
DISCUSSION
ISSUED AT 340 AM CST SAT MAR 1 2025
A COOLER DAY IN STORE ACROSS THE AREA AS SURFACE HIGH PRESSURE
CENTERED OVER SOUTH CENTRAL CANADA SETTLES INTO THE NORTHERN PLAINS
THROUGH THE DAY. WITH 850 MB COLD AIR ADVECTION CONTINUING, LOOK FOR
HIGHS CLOSE TO SEASONAL AVERAGES - RANGING FROM THE LOWER 30S IN
SOUTHWESTERN MN TO LOWER 40S THROUGH SOUTH CENTRAL SD. WITH HIGH
PRESSURE OVERHEAD, WINDS WILL BE ON THE LIGHT SIDE.
FOR TONIGHT AND SUNDAY, THE SURFACE RIDGE WILL SLIDE TO THE EAST OF
OUR AREA. THIS WILL BRING A RETURNING SOUTHERLY FLOW ON THE BACKSIDE
OF THE HIGH, AND WITH MIDLEVEL WARM AIR ADVECTION TEMPERATURES WILL
BEGIN TO MODERATE THROUGH THE PERIOD. THIS WILL PLAY OUT TO LOWS IN
THE UPPER TEENS TO MID 20S FOR TONIGHT, THEN WARMING INTO THE 50S TO
NEAR 60 ON SUNDAY. IT WILL BECOME BREEZY ON SUNDAY AFTERNOON IN A
TIGHTENING SPG AND STRONGER WINDS AT THE TOP OF THE MIXED LAYER -
AND WE COULD SEE A FEW GUSTS AROUND 25 MPH AT TIMES. THESE WINDS
WITH AFTERNOON RH VALUES RUNNING AROUND 30 TO 40 PERCENT WILL RESULT
IN AN ENHANCED FIRE DANGER - THOUGH MAINLY CONFINED TO THE HIGH
CATEGORY. AN UPPER LEVEL LOW LIFTS THROUGH THE CENTRAL AND SOUTHERN
PLAINS ON SUNDAY NIGHT, THOUGH LATEST GUIDANCE (WITH THE EXCEPTION
OF THE NAM) KEEPS ANY MEASURABLE PRECIPITATION WITH THE SYSTEM TO
THE SOUTH OF OUR AREA.
A SURFACE LOW BEGINS TO INTENSIFY OVER WESTERN NE AND KS ON MONDAY
AS AN UPPER LEVEL LOW BEGINS TO EJECT EASTWARD OUT OF THE
CENTRAL/SOUTHERN ROCKIES DURING THIS TIME FRAME. IN THE STRONG
SOUTHERLY FLOW OUT AHEAD OF THE SYSTEM, WARM AIR ADVECTION WILL
BOOST HIGHS INTO THE UPPER 50S TO LOWER 60S ACROSS OUR AREA ON
MONDAY AFTERNOON. ALTHOUGH IT WILL BE A SOMEWHAT BREEZY DAY,
INCREASING LOW LEVEL MOISTURE - WITH AFTERNOON RH OF 50 TO 60
PERCENT - WILL MITIGATE ANY FIRE DANGER FOR THAT DAY.
OUR ATTENTION THEN TURNS TO THE SYSTEM WHICH MAY IMPACT OUR
AREA FOR MONDAY NIGHT THROUGH TUESDAY NIGHT. MODELS ARE IN
FAIRLY DECENT AGREEMENT WITH THE AFOREMENTIONED UPPER LEVEL AND
SURFACE LOW TRACKING TRACKING FROM THE CENTRAL PLAINS TO THE
OHIO VALLEY THROUGH THE PERIOD - WITH SOME SLIGHT VARIATIONS ON
THE TRACK AND TIMING OF THE FEATURES. BOTH DETERMINISTIC MODELS
AND ENSEMBLES ARE INDICATING THIS SYSTEM BRINGING MEASURABLE
PRECIPITATION TO OUR AREA - AND SOME OF THIS MAY BE SNOW ON THE
BACKSIDE OF THE SYSTEM. IN ADDITION TO ANY PRECIPITATION, IN A
TIGHTENING SPG AND WINDS ALOFT RAMPING UP TO 40 TO 50 KTS IT
WILL BE A WINDY PERIOD. LATEST ENSEMBLES WOULD INDICATE A 30-50%
PROBABILITY OF AT LEAST 0.50" OF PRECIPITATION OVER NORTHWEST
IA INTO TUESDAY NIGHT. ENSEMBLES ALSO SUGGEST RAIN ON MONDAY
NIGHT AND EARLY TUESDAY, TRANSITIONING TO SNOW FROM WEST TO EAST
BY TUESDAY EVENING. EVEN SO, AT THIS TIME SNOWFALL AMOUNTS DO
NOT LOOK EXCESSIVE, WITH PROBABILITIES OF ONLY 10-20% FOR AT
LEAST 2 INCHES, BUT A 20-40% PROBABILITY OF 1 INCH OF
ACCUMULATION. ALL OF THESE ELEMENTS WILL BE DEPENDENT ON THE
EVENTUAL TRACK OF THE SYSTEM, BUT IT WILL BE SOMETHING TO KEEP
AND EYE ON WITH THE POTENTIAL FOR AT LEAST SOME MODERATE
IMPACTS.
WITH THE DEPARTURE OF THIS SYSTEM, TEMPERATURES WILL FALL BACK TO
NEAR NORMAL FOR WEDNESDAY, BEFORE TEMPERATURES MODERATE BACK TO
ABOVE NORMAL LEVELS FOR THURSDAY AND FRIDAY. LATEST MODEL GUIDANCE
SUGGESTS ANOTHER ROUND OF PRECIPITATION WILL BE POSSIBLE FOR LATER
ON THURSDAY INTO FRIDAY, THOUGH MODEL DIFFERENCES PRECLUDE BUYING IN
ON ANY ONE SOLUTION.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1104 AM CST SAT MAR 1 2025
VFR THROUGH THE PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...JM
AVIATION...08
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