439
FXUS63 KFSD 032100
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
300 PM CST MON FEB 3 2025
KEY MESSAGES
- ONGOING LIGHT FREEZING DRIZZLE AND/OR LIGHT SNOW/FLURRIES ARE
EXPECTED TO WIND DOWN BY AROUND SUNSET THIS EVENING.
- COOLER THAN NORMAL CONDITIONS CONTINUE TUESDAY, BUT
TEMPERATURES REBOUND TO NEAR NORMAL WEDNESDAY THROUGH NEXT
WEEKEND.
- ADDITIONAL CHANCES FOR LIGHT PRECIPITATION MIDWEEK (20-40%
CHANCE FOR LIGHT SNOW OR FREEZING DRIZZLE WEDNESDAY) AND AGAIN
LATE THIS WEEK (40-80% CHANCE OF MEASURABLE SNOW FRIDAY NIGHT-
SATURDAY, HIGHEST NORTH OF I-90).
DISCUSSION
ISSUED AT 257 PM CST MON FEB 3 2025
LATE THIS AFTERNOON-TUESDAY: AS TEMPERATURES CONTINUE TO SLOWLY FALL
WITH COLD ADVECTION THIS AFTERNOON, WE HAVE SEEN EARLIER AREAS OF
FREEZING DRIZZLE BEGIN TO CHANGE TO FLURRIES/LIGHT SNOW IN MANY
AREAS OF SOUTHEAST SOUTH DAKOTA, AND NORTHERN PORTIONS OF SOUTHWEST
MINNESOTA (NORTH OF HIGHWAY 30). STILL SEEING EVIDENCE OF LIGHT
ICING ONGOING WITHIN PARTS OF THE ADVISORY AREA, THOUGH SO WILL HANG
ON TO THE WINTER WEATHER ADVISORY THROUGH 4 PM. LOOKS LIKE OVERALL
INTENSITY OF LINGERING PRECIPITATION SHOULD DIMINISH ENOUGH TO LIMIT
ADDITIONAL IMPACTS AFTER THAT TIME.
THIS BRIEF COOLDOWN WILL PERSIST THROUGH TOMORROW, WITH LOWS TONIGHT
IN THE SINGLE DIGITS ABOVE ZERO EXPECTED FOR MOST AREAS, AND HIGHS
TUESDAY MAINLY TEENS NORTH TO MID 20S SOUTH. MODEST NORTHEAST TO
EAST WINDS 10-20 MPH WILL PUSH WIND CHILLS INTO THE SINGLE DIGITS
AND TEENS BELOW ZERO TONIGHT THROUGH TUESDAY MORNING, BUT NOTHING
CLOSE TO ADVISORY LEVEL WIND CHILLS ARE EXPECTED.
WEDNESDAY: WARM ADVECTION AHEAD OF AN APPROACHING WAVE WILL LIMIT
OUR TEMPERATURE FALL TUESDAY NIGHT, WITH READINGS ON WEDNESDAY
EXPECTED TO REBOUND INTO THE MID-UPPER 20S NORTHEAST TO MID 30S
SOUTHWEST FOR HIGHS. THIS WARM ADVECTION AND ASSOCIATED MID-UPPER
LEVEL WAVE WILL BRING A CHANCE OF LIGHT PRECIPITATION, MAINLY TO
AREAS NEAR/EAST OF I-29. PRECIPITATION TYPE WILL BE A CHALLENGE,
ESPECIALLY AT THIS RANGE WITH MODELS LACKING AGREEMENT REGARDING THE
STRENGTH OF A WARM LAYER ALOFT, AS WELL AS AVAILABILITY OF MOISTURE
WITHIN THE ICE-PRODUCTION LAYER. WITH SURFACE TEMPERATURES LARGELY
REMAINING SUB-FREEZING DURING THE PERIOD OF BETTER PRECIPITATION
CHANCES, THERE WILL BE A CHANCE FOR LIGHT ICING NEAR/EAST OF I-29
DURING THE DAYTIME HOURS ON WEDNESDAY. HOWEVER, CURRENT CONFIDENCE
IS ON THE LOW SIDE REGARDING WHERE ANY DIVIDING LINE BETWEEN LIGHT
SNOW AND/OR ICE MAY OCCUR, AS WELL AS ANY POTENTIAL ACCUMULATIONS.
THOSE WITH TRAVEL PLANS ON WEDNESDAY WILL WANT TO MONITOR FOR THE
LATEST UPDATES ON THIS POTENTIAL FOR MIXED PRECIPITATION. AS WE SAW
WITH TODAY'S LIGHT FREEZING DRIZZLE, IT DOES NOT TAKE MUCH ICING ON
UNTREATED SURFACES TO CAUSE AT LEAST MINOR TRAVEL HEADACHES.
THURSDAY-SATURDAY: THURSDAY LOOKS TO BE A RELATIVELY QUIET DAY
BETWEEN WAVES, BUT THE NEXT SURGE OF WEAK WARM ADVECTION AHEAD OF A
BROAD TROUGH COULD BEGIN TO PRODUCE SOME LIGHT SNOW ACROSS NORTHERN
PORTIONS OF THE AREA AS EARLY AS LATE THURSDAY NIGHT/FRIDAY. MODELS
ARE ACTUALLY IN PRETTY GOOD AGREEMENT ON THE TIMING OF THE BROAD
TROUGH, WHICH SHOULD PRODUCE OUR BEST CHANCE FOR AT LEAST SOME LIGHT
SNOW LATE FRIDAY NIGHT INTO SATURDAY. AT THE PRESENT TIME, MOISTURE
AVAILABILITY AND COLD TEMPERATURES BOTH SEEM SUFFICIENT ENOUGH THAT
WE SHOULD ONLY HAVE TO WORRY ABOUT SNOW WITH THIS SYSTEM. THE MAIN
QUESTION WILL BE WHETHER A NARROW ZONE OF MID-LEVEL FRONTOGENESIS
WILL FOCUS A HEAVIER BAND SOMEWHERE NORTH OF I-90, PERHAPS EVEN
NORTH OF HIGHWAY 14, WHICH IS WHERE ENSEMBLES PLACE THE HIGHEST
(>70%) PROBABILITIES OF SEEING 0.10" OR MORE LIQUID PRECIPITATION
FRIDAY NIGHT-SATURDAY. THESE PROBABILITIES TAPER OFF TO THE SOUTH,
WITH LATEST ENSEMBLES SHOWING <30% OF SIMILAR AMOUNTS NEAR THE
MISSOURI RIVER VALLEY.
SUNDAY-MONDAY: THE SYSTEM SHOULD EXIT RELATIVELY QUICKLY WITH DRY
WEATHER RETURNING FOR THE LATTER HALF OF THE WEEKEND. DIVERGENT
MODELS BY THE END OF THIS FORECAST PERIOD LEND LITTLE CONFIDENCE IN
PRECIPITATION CHANCES AND TEMPERATURE TRENDS AS WE HEAD INTO EARLY
NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1103 AM CST MON FEB 3 2025
MVFR-IFR STRATUS WILL PERSIST ACROSS MUCH OF THE AREA THROUGH
SUNSET, THOUGH GRADUAL IMPROVEMENT IS FORECAST FROM WEST TO EAST
WITH PORTIONS OF SOUTHWEST MINNESOTA/NORTHWEST IOWA SEEING
POTENTIAL FOR IFR CEILINGS PERSIST THE LONGEST.
ALONG WITH THE MVFR-IFR CEILINGS WILL BE AREAS OF MVFR-IFR
VISIBILITY IN EITHER -FZDZ OR FLURRIES. AS WITH THE LOWER STRATUS,
LOWER VISIBILITY AND POTENTIAL FOR FREEZING DRIZZLE WILL PERSIST
LONGEST ACROSS SOUTHWEST MN AND INTO THE IOWA GREAT LAKES DUE TO
HIGHER ELEVATION AND A WEAK UPSLOPE NORTH-NORTHEAST FLOW.
OVERALL, IMPROVING CONDITIONS ARE EXPECTED AFTER 04/00Z-02Z WITH
VFR CONDITIONS EXPECTED TO PREVAIL FOR THE LATTER HALF OF THE TAF
PERIOD.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...WINTER WEATHER ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR
MNZ071-072-080-081-089-090-097.
IA...WINTER WEATHER ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR
IAZ002-003.
NE...NONE.
DISCUSSION...JH
AVIATION...JH
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