556
FXUS63 KFSD 041731
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1131 AM CST TUE FEB 4 2025
KEY MESSAGES
- COLD WIND CHILLS BELOW ZERO CONTINUE EARLY THIS AFTERNOON.
- CONFIDENCE IS DECREASING IN POTENTIAL FOR FREEZING DRIZZLE
ALONG AND EAST OF I-29 WEDNESDAY INTO WEDNESDAY NIGHT DUE TO
SLOWER AND DRIER MODEL DATA. WILL HAVE MORE UPDATES THIS
AFTERNOON WITH THE FULL FORECAST PACKAGE.
- ANOTHER CHANCE (50-90% CHANCE) FOR MEASURABLE SNOW WILL RETURN
TO THE AREA FRIDAY NIGHT THROUGH SATURDAY. LOCATIONS ALONG AND
NORTH OF I-90 HAVE THE HIGHEST CHANCE FOR SEEING SNOW.
DISCUSSION
ISSUED AT 341 AM CST TUE FEB 4 2025
QUIET CONDITIONS PERSIST ACROSS THE AREA THIS MORNING AS LOW, MID,
AND HIGH CLOUDS SIT OVER PARTS OF THE AREA. SURFACE HIGH PRESSURE
CONTINUES TO TRACK EASTWARDS ACROSS NORTH DAKOTA, PROVIDING COLD
NORTHERLY WINDS ACROSS THE AREA. THIS WILL ALSO RESULT IN COLDER
WIND CHILLS DOWN TO THE NEGATIVE SINGLE DIGITS TO DOWN TO ABOUT
-20F ALONG THE BUFFALO RIDGE IN SOUTHWEST MINNESOTA. MAKE SURE TO
BUNDLE UP AS YOU HEAD OUT THE DOOR THIS MORNING! DESPITE THE HIGH
SLOWLY DEPARTING TO THE EAST, THE NORTH/NORTHEAST WINDS FROM THE
HIGH AND ABUNDANT CLOUD COVER WILL MAKE FOR A COLD DAY ACROSS THE
AREA WITH HIGHS ONLY WARMING TO THE TEENS AND 20S. ALTHOUGH WIND
CHILLS WILL IMPROVE THROUGHOUT THE DAY, THEY WILL ONLY WARM TO
EITHER SIDE OF 0F. EASTERLY FLOW AND PERSISTENT CLOUD COVER WILL
KEEP LOW TEMPERATURES A BIT WARMER, ONLY FALLING TO THE SINGLE
DIGITS AND TEENS.
THE NEXT CHANCE FOR PRECIPITATION COMES ON WEDNESDAY AS AN UPPER
LEVEL WAVE AND ASSOCIATED JET ALOFT EJECT INTO THE NORTHERN PLAINS.
WARM AIR ADVECTION (WAA) WILL STRENGTHEN AHEAD OF THE INCOMING WAVE
WHILE TURNING WINDS IN THE LOWEST KILOMETER SOUTHERLY. THIS WILL
ADVECT IN BETTER LOW LEVEL MOISTURE BUT THE QUALITY OF THIS MOISTURE
REMAINS QUESTIONABLE. THERMAL PROFILES LOOK TO REMAIN GENERALLY
BELOW FREEZING PER HREF PROBABILITIES AND BUFKIT SOUNDINGS. HOWEVER,
THE SOUNDINGS DO SHOW TEMPERATURES WARMING ABOVE FREEZING AT AND
ABOVE 700 MB. THIS CREATES A BIT OF UNCERTAINTY AS THE WARM NOSE
WILL BE LARGELY DRY BUT THE LOWEST KILOMETER WILL BE SATURATED. THE
DENDRITIC GROWTH ZONE (DGZ) WILL LIE ABOVE THE 700 MB WARM NOSE AND
ONLY BE WEAKLY SATURATED AT TIMES. THIS COULD LEAD TO SOME VERY
LIGHT SNOW BUT CONFIDENCE IS LOW (<20% CHANCE) IN THIS POTENTIAL.
CONFIDENCE IS HIGHER IN THE MAIN PRECIPITATION TYPE BEING FREEZING
DRIZZLE GIVEN THE GENERALLY DRY DGZ. HIGH TEMPERATURES WILL ONLY
WARM TO THE MID 20S TO MID 30S ACROSS THE AREA BUT TEMPERATURES
ABOVE FREEZING WILL BE LOCATED ACROSS CENTRAL AND SOUTH CENTRAL
SOUTH DAKOTA. THIS IS THE SAME AREA WHERE PRECIPITATION IS NOT
EXPECTED. AS OF NOW, THE BEST SATURATION AND MIXED PRECIPITATION
WILL FALL ALONG AND EAST OF I-29. THIS LOOKS TO RESULT IN LIGHT
ICING THROUGHOUT THE DAY BUT ESPECIALLY DURING THE AFTERNOON HOURS
WHEN THE BETTER LOW LEVEL MOISTURE ARRIVES. THE FORECAST MAY STILL
CHANGE THOUGH DUE TO THE BREEZY WINDS. THE SURFACE PRESSURE GRADIENT
(SPG) WILL REMAIN TIGHTENED ACROSS THE AREA, KEEPING BREEZY
SOUTHEASTERLY WINDS GOING THROUGHOUT THE DAY. THIS COULD INCREASE
THE ICE TO LIQUID RATIO RESULTING IN SLIGHTLY MORE EFFICIENT ICE
ACCUMULATIONS. AS OF NOW, STILL THINK THAT ICE AMOUNTS WON'T BE MORE
THAN A LIGHT GLAZE BUT CAN'T FULLY RULE OUT ISOLATED AMOUNTS UP TO
ABOUT 5 HUNDREDTHS OF AN INCH. ANY CHANCE FOR PRECIPITATION WILL EXIT
THE AREA WEDNESDAY EVENING, LEAVING QUIET CONDITIONS FOR THE
OVERNIGHT HOURS. LOW TEMPERATURES WILL FALL TO THE TEENS OVERNIGHT.
THURSDAY WILL BE A QUIET DAY AS HIGH PRESSURE PUSHES INTO THE
NORTHERN PLAINS. A SHOT OF COLD AIR ADVECTION (CAA) WILL KEEP BREEZY
WINDS GOING THROUGH MOST OF THE DAY. HOWEVER, WINDS WILL TURN TO OUT
OF THE NORTHWEST, RESULTING IN UNIDIRECTIONAL WIND PROFILES. THIS
WILL CREATE EFFICIENT MIXING ACROSS THE AREA RESULTING IN GUSTS UP
TO ABOUT 30 MPH. DESPITE THE CAA, HIGH TEMPERATURES WILL WARM A BIT
MORE TO THE UPPER 20S AND 30S ACROSS THE AREA. LOWS WILL FALL TO THE
SINGLE DIGITS AND TEENS.
FRIDAY WILL ALSO BE QUIET THROUGHOUT THE DAY AS THE CENTER OF THE
PREVIOUSLY MENTIONED SURFACE HIGH SLIDES ACROSS THE FORECAST AREA.
THIS WILL MAKE FOR MUCH LIGHTER WINDS BUT WILL KEEP HIGHS IN THE MID
20S AND 30S. THINGS BEGIN TO CHANGE FRIDAY NIGHT THOUGH AS ANOTHER
UPPER WAVE WILL EJECT INTO THE NORTHERN PLAINS FROM THE ROCKIES.
THIS WAVE WILL DELIVER THE SECOND ROUND OF PRECIPITATION TO THE AREA
IN THE FORM OF SNOW. ENSEMBLES ARE IN DECENT AGREEMENT IN SNOW
RETURNING TO THE AREA AS THEY SHOW A BROAD 50-90% CHANCE FOR LIQUID
QPF TO EXCEED A TENTH OF AN INCH. THE HIGHEST PROBABILITIES LIE
ALONG AND NORTH OF I-90, ESPECIALLY TOWARDS HIGHWAY-14. THE SNOW
LOOKS TO BEGIN FALLING FRIDAY NIGHT BUT THE MAJORITY OF THE SNOW
WILL FALL THROUGHOUT THE DAY ON SATURDAY. THIS EVENT LOOKS TO BE A
BANDED SNOWFALL EVENT SIMILAR TO WHAT WE SAW EARLIER THIS WEEK. THE
EURO EXTREME FORECAST INDEX (EFI) CONTINUES TO REMAIN CONSISTENT
WITH 70-80% PERCENT OF ITS MEMBERS POINTING TO AN ANOMALOUS EVENT
ALONG AND NORTH OF I-90. WHILE THE ENSEMBLES ARE IN SUPPORT OF THE
SNOW, DO THINK IT IS WORTH NOTING THAT LIKE THE PREVIOUS SYSTEM
EARLIER THIS WEEK, SMALL CHANGES IN THE SYSTEMS TRACK CAN RESULT IN
MEANINGFUL CHANGES TO THE FORECAST. AS OF NOW, HAVE CONTINUED WITH
MODEL BLENDED POPS GIVEN THE UNCERTAINTY IN WHERE THIS POTENTIAL
BAND WILL SET UP. OUTSIDE OF SNOW CHANCES, HIGH TEMPERATURES WILL
REMAIN COOL, ONLY WARMING TO THE 20S TO UP TO ABOUT FREEZING ALONG
HIGHWAY-20. ANY CHANCE FOR SNOW LOOKS TO PUSH EAST OF THE AREA BY
SATURDAY EVENING. LOW TEMPERATURES LOOK TO FALL TO THE SINGLE DIGITS
BUT THIS COULD CHANGE DEPENDING ON THE SNOWPACK THAT IS LEFT OVER
FROM THE FALLING SNOW.
SUNDAY WILL BE A QUICK BREAK IN THE ACTION BEFORE ANOTHER WAVE MOVES
IN ALOFT EARLY NEXT WEEK. THIS WAVE COULD BRING ANOTHER ROUND OF
SNOW TO THE AREA BUT THIS CHANCE IS UNCERTAIN AT THIS TIME GIVEN HOW
MEDIUM RANGE GUIDANCE VARIES IN THE WAVES EVOLUTION. WILL KEEP AN
EYE ON THIS POTENTIAL OVER THE COMING DAYS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1121 AM CST TUE FEB 4 2025
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD, WITH PREVAILING
MID AND HIGH CLOUDS. COULD SEE SOME STRATUS (AROUND 3-4KFT)
WEDNESDAY MORNING AND AFTERNOON. WINDS SHIFT THROUGH THE PERIOD
BECOMING SOUTHEASTERLY BY MID MORNING WEDNESDAY. GUSTS AROUND
15-25 KNOTS ARE EXPECTED AS WELL.
CAN'T RULE OUT SOME VERY LIGHT WINTRY PRECIPITATION, INCLUDING
FREEZING DRIZZLE, FOR AREAS ALONG AND EAST OF I-29 THROUGH THE
DAY ON WEDNESDAY. LATEST MODELS ARE SHIFTING DRIER AND LATER, SO
WILL CONTINUE TO OMIT MENTION FROM KFSD AND KSUX.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
DISCUSSION...MEYERS
AVIATION...SG
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