793
FXUS63 KFSD 311709
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1109 AM CST FRI JAN 31 2025
KEY MESSAGES
- A BIT COOLER WITH HIGHS IN THE UPPER 30S AND 40S TODAY BUT
WELL ABOVE NORMAL TEMPERATURES IN THE 40S AND LOW 50S ON
SATURDAY. SUNDAY WILL SEE MILD HIGHS BUT LIKELY SOME FALLING
AFTERNOON TEMPERATURES.
- A BAND OF SNOW WILL BE POSSIBLE SUNDAY NIGHT INTO MONDAY WITH
DECENT AGREEMENT AMONGST THE MODELS ON SOME ACCUMULATIONS
ESPECIALLY NORTH OF I-90. MONDAY MORNING COULD SEE SOME SLOWER
COMMUTE TIMES AND SLICK ROADS.
- NO SIGNIFICANT WINTER STORMS EXPECTED NEXT WEEK, BUT NEAR TO
BELOW NORMAL TEMPERATURES AND MULTIPLE CHANCES (20-50 PERCENT)
FOR LIGHT SNOW ARE EXPECTED.
DISCUSSION
ISSUED AT 256 AM CST FRI JAN 31 2025
LOW PRESSURE TO THE SOUTH WILL TUG SLIGHTLY COLDER AIR SOUTHWARD
TODAY WITH HIGHS RUNNING ABOUT 10-15 DEGREES COOLER THAN THURSDAY.
EVEN WITH THIS FAIRLY SIGNIFICANT DROP IN TEMPERATURES, HIGHS WILL
STILL BE A SOLID 10-15 DEGREES ABOVE NORMAL, GENERALLY IN THE 40S.
A FAST MOVING UPPER LEVEL RIDGE WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING AHEAD OF A FAST MOVING WAVE THAT MOVES
THROUGH THE DAKOTAS LATE TONIGHT INTO SATURDAY. ANALYSIS OF MODEL
SOUNDINGS SUGGESTS THAT PRECIPITATION FROM THIS FAST MOVING WAVE IS
VERY UNLIKELY. SATURATION AND FORCING IN THE DENDRITIC LAYER IS NOT
TOO BAD, BUT THIS LAYER IS FOUND ROUGHLY FROM 600-500 MB, WITH A
FAIRLY SIGNIFICANT DRY LAYER BELOW THIS. SOME HINTS THAT WE MAY SEE
A LITTLE STRATUS, BUT FROM ABOUT 650 MB TO 900 MB IT IS VERY DRY.
THERE IS SOME VERY WEAK INSTABILITY AROUND THE DENDRITIC LAYER AND
THE DRY LAYER IS NOT QUITE AS DRY CLOSER TO HIGHWAY 14 INTO
SOUTHWEST MN, SO MAYBE A SPRINKLE OR VERY LIGHT SHOWER. THE OVERALL
MESSAGE IS THAT SATURDAY WILL SEE QUITE A BIT OF CLOUD COVER, BUT
VERY LITTLE PRECIPITATION.
AS THIS SYSTEM MOVES EAST, A STRONG JET AND WAVE WILL MOVE ONTO THE
WESTERN HIGH PLAINS SUNDAY, WHICH WILL DRAG COLDER AIR SOUTHWARD
SUNDAY AFTERNOON AND SUNDAY NIGHT. PRECIPITATION WITH THIS INITIAL
COLD PUSH SUNDAY AFTERNOON AND SUNDAY EVENING DOES NOT LOOK VERY
LIKELY. HOWEVER SUNDAY NIGHT INTO MONDAY A WAVE WILL MOVE OUT OF
WYOMING AND INTERACT WITH THE LOW AND MID LEVEL THERMAL GRADIENT
THAT IS LEFT BEHIND BY THE EARLIER SUNDAY WAVE. SOUTHERLY FLOW WILL
DEVELOP AHEAD OF THIS WAVE AND BRING A DECENT SHOT OF FORCING WITH A
GOOD CHANCE FOR A BAND OF FRONTAL PRECIPITATION. THE LOW LEVELS WILL
ONCE AGAIN STRUGGLE A BIT TO SATURATE, BUT LATER SUNDAY NIGHT INTO
MONDAY MORNING THE SOUNDINGS ARE SUPPORTIVE OF SOME SNOWFALL. FOR
NOW THE BETTER CHANCES APPEAR TO BE NEAR AND NORTH OF I-90,
ESPECIALLY ON THE SD SIDE. THE LATEST EC ENSEMBLE AND GEFS 50TH
PERCENTILE SUGGESTS A BAND OF 1-2" OF SNOW WITH THE 75TH PERCENTILE
MORE IN LINE WITH 2-4". THE GEFS IS A BIT FARTHER NORTH AND CLOSER
TO HIGHWAY 14.
ANY SNOW THE DEVELOPS WILL LIKELY BE DONE BY MONDAY AFTERNOON, BUT
ANOTHER SYSTEM MOVES INTO THE AREA TUESDAY INTO WEDNESDAY WITH ONLY
MARGINAL AGREEMENT ON THIS ENERGY. WILL HAVE SOME SMALLER CHANCES
FOR SNOW DURING THIS TIME AND TAKE A WAIT AND SEE APPROACH TO ANY
POTENTIAL SNOW FOR MID TO LATE WEEK NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1106 AM CST FRI JAN 31 2025
MVFR TO IFR CEILINGS MAY LINGER OVER PORTIONS OF NORTHEASTERN SD
AND NORTHCENTRAL SD INTO THE AFTERNOON. HOWEVER NOT ANTICIPATING
THIS ACTIVITY REACHING FURTHER SOUTH.
WE'LL SEE HIGH LEVEL CLOUDS INCREASE AFTER DARK AS INFLUENCE
FROM APPROACHING SYSTEM ARRIVES. WINDS MAY ALSO TURN LIGHT AND
VARIABLE, SWITCHING TO EAST SOUTHEAST AFTER MIDNIGHT.
BY DAYBREAK, CEILINGS WILL CONTINUE TO LOWER AND MAY APPROACH
THE 5K FT AGL RANGE BY MID-MORNING. WIND GUSTS WILL ALSO
INCREASE, POTENTIALLY GUSTING TO 25 TO 35 KNOTS BY MID-DAY.
CAN'T RULE OUT SOME VERY LIGHT PRECIPITATION DEVELOPING BY MID-
MORNING, BUT PROBABILITIES FAR TOO LOW TO INDICATE AT THIS TIME.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...08
AVIATION...DUX
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