904
FXUS63 KFSD 052308
AFDFSD
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
508 PM CST WED MAR 5 2025
KEY MESSAGES
- ANOTHER ROUND OF PRECIPITATION IS LIKELY THURSDAY NIGHT INTO
EARLY FRIDAY. CHANCES FOR SNOW LOOK TO BE MAINLY CONFINED TO
THE MISSOURI RIVER VALLEY WHERE A FEW INCHES OF SNOW IS
POSSIBLE.
- ABOVE AVERAGE TEMPERATURES LOOK TO RETURN TO THE AREA THIS
WEEKEND AND PERSISTS INTO EARLY NEXT WEEK. HIGH TEMPERATURES
HAVE A 30-60% CHANCE TO EXCEED 60 DEGREES F.
DISCUSSION
ISSUED AT 244 PM CST WED MAR 5 2025
YESTERDAY'S POWERFUL STORM SYSTEM CONTINUES TO PUSH EASTWARDS THIS
AFTERNOON. THE SURFACE PRESSURE GRADIENT IS LOOSENING ACROSS THE
AREA AS SURFACE RIDGING BEGINS TO PUSH IN FROM THE WEST, THUS
WEAKENING WINDS. DESPITE THE WEAKENING WINDS, AREAS OF BLOWING SNOW
IS STILL EXPECTED FOR THE REST OF THE AFTERNOON HOURS DUE TO LAST
NIGHTS SNOWFALL AND REMAINING STRONGER WINDS. WHILE VISIBILITIES ARE
EXPECTED TO CONTINUE TO IMPROVE, LOCATIONS ALONG AND EAST OF HIGHWAY-
59 WILL STILL SEE BLIZZARD CONDITIONS/BLOWING SNOW IMPACTS THROUGH
THE REST OF THE AFTERNOON HOURS. THESE CONDITIONS COULD AFFECT THE
EVENING COMMUTE. COME THE EVENING HOURS, WINDS WILL FINALLY BEGIN TO
MORE RAPIDLY WEAKEN, ENDING BLOWING SNOW IMPACTS FOR THIS AREA.
LIGHT AND VARIABLE WINDS ARE EXPECTED FOR THE OVERNIGHT HOURS WITH
LOW TEMPERATURES DROPPING TO THE TEENS AND 20S.
THURSDAY WILL BE A MOSTLY QUIET DAY AS UPPER LEVEL RIDGING QUICKLY
PUSHES THROUGH THE NORTHERN PLAINS. THIS WILL ALLOW FOR HIGH
TEMPERATURES TO WARM TO THE UPPER 30S AND LOW TO MID 40S. CLOUDS
WILL BE BUILDING IN ALOFT THROUGH AHEAD OF THE NEXT CHANCE FOR
PRECIPITATION. THIS CHANCE WILL BEGIN DURING THE LATE AFTERNOON
HOURS ALONG THE MISSOURI RIVER AS HEIGHTS BEGIN TO FALL ALOFT AHEAD
OF AN INCOMING WAVE. THIS SYSTEM LOOKS TO BE DRIVEN BY STRONG
FRONTOGENESIS (FGEN) BETWEEN 700-600 MB. VERTICAL CROSS SECTIONS
REVEAL WEAKER STABILITY ABOVE THE FGEN AND DECENT OMEGA (LIFT) IN
THE DENDRITIC GROWTH ZONE (DGZ). GIVEN THE ANTICYCLONIC CURVATURE IN
THE GEOPOTENTIAL HEIGHT FIELD ALOFT, NEGATIVE EQUIVALENT POTENTIAL
VORTICITY (EPV) COULD OCCUR ABOVE THE FGEN SURFACE. GIVEN THE ABOVE
FREEZING HIGH TEMPERATURES, PRECIPITATION WILL BEGIN AS RAIN LATE
THURSDAY AFTERNOON BEFORE TRANSITIONING TO SNOW DURING THE EVENING
AND OVERNIGHT HOURS. THE SNOW WILL PUSH SOUTHEAST OF THE AREA DURING
THE AFTERNOON HOURS ON FRIDAY. IN TERMS OF SNOWFALL, LATEST
ENSEMBLES SHOW A 50-90% CHANCE FOR SNOWFALL TOTALS TO EXCEED 2
INCHES ALONG THE MISSOURI RIVER. GIVEN THAT THIS WILL BE A BANDED
EVENT, THE ENSEMBLES SHOW A TIGHT GRADIENT IN THEIR PROBABILITIES UP
TOWARDS I-90. WHILE SOME VERY LIGHT SNOW IS POSSIBLE UP TO THE
INTERSTATE, THE HIGHEST TOTALS LOOK TO FALL ALONG THE MISSOURI RIVER
VALLEY. CONSIDERATION WAS GIVEN TO ISSUE A WINTER WEATHER ADVISORY
BUT HAVE DECIDED TO HOLD OFF AT THIS TIME AS SMALL SHIFTS IN THE
BANDS PLACEMENT CAN HAVE MEANINGFUL CHANGES ON SNOWFALL AMOUNTS.
ALSO, IF STRONGER EPV IS REALIZED, THEN A TIGHTER SNOWBAND WILL BE
POSSIBLE, AGAIN AFFECTING SNOWFALL TOTALS. TRENDS WILL BE CAREFULLY
MONITORED WITH THIS SYSTEM.
FRIDAY WILL SEE SNOW CHANCES DWINDLING AS THEY PUSH SOUTHEAST OF THE
AREA. THIS WILL ALLOW FOR HIGH TEMPERATURES TO WARM TO THE 30S TO
MID 40S, WARMEST ACROSS PARTS OF CENTRAL SOUTH DAKOTA. DRY
CONDITIONS ARE EXPECTED BEGINNING FRIDAY EVENING. LOW TEMPERATURES
WILL FALL TO TEENS AND 20S OVERNIGHT.
AN EXTENDED PERIOD OF DRY CONDITIONS BEGINS THIS WEEKEND WHILE
TEMPERATURES WARM TO ABOVE AVERAGE LEVELS. THIS IS DUE TO UPPER
LEVEL RIDGING OVER THE WESTERN CONUS PUSHING EASTWARDS INTO THE
PLAINS. HIGHS THIS WEEKEND LOOK TO WARM TO THE 40S, 50S, AND
POSSIBLY 60S. SUNDAY WILL BE THE WARMEST DAY THIS WEEKEND.
THE PREVIOUSLY MENTIONED RIDGING FLATTENS FOR NEXT WEEK, RESULTING
IN SOMEWHAT ZONAL FLOW. DESPITE THE ZONAL FLOW, ABOVE AVERAGE
TEMPERATURES LOOK TO CONTINUE. HIGHS COULD REMAIN IN THE 60S ACROSS
THE AREA BEFORE COOLING DOWN NEXT WEDNESDAY. ENSEMBLES SUPPORT THIS
POTENTIAL AS THEY SHOW A 30-60% CHANCE FOR HIGHS TO EXCEED 60F NEXT
MONDAY AND TUESDAY. THIS IS FURTHER SUPPORTED BY EURO EXTREME
FORECAST INDEX (EFI) AS IT SHOWS 50-70% OF ITS MEMBERS SUGGESTING
ANOMALOUS WARMTH FOR THIS PERIOD OF TIME. ALL THIS TO SAY THAT ABOVE
AVERAGE HIGH TEMPERATURES ARE LIKELY NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 505 PM CST WED MAR 5 2025
NORTHWEST WINDS WILL QUICKLY DIMINISH AFTER SUNSET. A BATCH OF
MID LEVEL CLOUDS WILL MOVE THROUGH THE AREA THIS EVENING INTO
THE EARLY OVERNIGHT HOURS. MID LEVEL CLOUDS WILL INCREASE FROM
THE SOUTHWEST ON THURSDAY AFTERNOON WITH SOME LIGHT RAIN OR
LIGHT SNOW POSSIBLE NEAR THE MISSOURI RIVER AFTER ABOUT 22Z
THURSDAY. THE BETTER CHANCES FOR SNOW AND IFR CONDITIONS WILL BE
SOUTH OF I-90 THURSDAY EVENING INTO FRIDAY MORNING.
FSD WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ072-
080-089.
BLIZZARD WARNING UNTIL 6 PM CST THIS EVENING FOR MNZ081-090.
IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ002-
013-021-031.
BLIZZARD WARNING UNTIL 6 PM CST THIS EVENING FOR IAZ003-014-
022-032.
NE...NONE.
DISCUSSION...MEYERS
AVIATION...08
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