656 FXUS63 KFSD 261849 AFDFSDArea Forecast Discussion National Weather Service Sioux Falls SD 149 PM CDT Fri Sep 26 2025
.KEY MESSAGES...
- Aside from a brief cooldown Saturday, the week ahead will be dominated by well above normal temperatures and breezy southerly winds.
- Dry conditions will continue through the middle of next week, with low precipitation chances returning by Thursday-Friday.
- Occasional breezy afternoons and drying grasses may lead to localized elevated fire weather concerns, mainly toward south- central South Dakota today and early next week.
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.DISCUSSION... Issued at 148 PM CDT Fri Sep 26 2025
A cool front moves through overnight tonight. As the front passes, lapse rates increase and weak instability develops, but dry air will not allow for any showers or thunderstorms to develop, so not looking for any precipitation. Late tonight into Saturday morning cold advection and 30-35 knot winds around 925 mb could lead to some breezy conditions, before high pressure builds further south which will bring decreasing winds through the afternoon and evening. May be a scenario where there is about an hour of higher wind gusts during peak cold air advection, then the wind settles back to a more normal gustiness. Saturday morning lows will be mild with winds keeping temperatures up in the mid to upper 50s in most locations. Highs Saturday will mostly be in the 70s, and with decreasing winds and dew points in the 30s and 40s it will be a cool and pleasant evening.
Surface high pressure locks in east of the area through Sunday morning which will keep light winds in place east of I-29. Southerly flow rebounds through the night west of I-29. Lows in the 40s where winds are light and 50 to 55 near and west of the James River. Right now even with the light winds fog does not look likely with the dry air mass in place.
Upper level high pressure is expected to lock into place over the mid Mississippi Valley through late week, keeping southerly flow in place across the northern and central Plains. This continues to show support for dry, very warm and occasionally breezy conditions. With morning lows only falling into the upper 50s to lower 60s and highs topping out daily in the 80s the temperatures will be running about 10 to 15 degrees above normal through the week. For now records are not expected with record highs in most locations from the lower to mid 90s.
With this heat and increase in southerly flow fire weather will gradually become more concerning through the week as fuels rapidly cure. By the end of the week if the small chances for rain erode or produce very little precipitation, then we may move into a period with heightened fire weather concerns.
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.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/... Issued at 1205 PM CDT Fri Sep 26 2025
VFR through the period. Southerly winds will gust around 20-25 mph at times this afternoon. Overnight into Saturday morning, a wind shift will move through and turn winds to the northwest. A few gusts of 25 to 30 mph will be possible with this frontal passage before winds quickly diminish on Saturday afternoon as surface high pressure builds south.
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.FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None.
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DISCUSSION...08 AVIATION...08
NWS FSD Office Area Forecast Discussion