137 FXUS63 KFSD 291642 AFDFSDArea Forecast Discussion National Weather Service Sioux Falls SD 1142 AM CDT Mon Sep 29 2025
.KEY MESSAGES...
- Well above normal temperatures continue through the upcoming week. A record or two may fall today and potentially Thursday and Friday.
- Dry conditions are expected through most of the work week. A few daybreak sprinkles/showers are possible through the first half of the week, but chances remain < 20%.
- Dry and breezy afternoon conditions over the next week could lead to low end fire weather concerns as fire fuels continue to dry out.
- Next reasonable risk for widespread rain arrives by and into next weekend, with a cool down in temperatures.
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.DISCUSSION... Issued at 318 AM CDT Mon Sep 29 2025
NOW THROUGH TONIGHT: A warmer start to the day with temperatures this morning in the 50s to mid 60s. Mid level clouds are beginning to increase across south central SD in response to the strengthening LLJ and a weak wave moving through. Can`t rule out some sprinkles with some returns on radar at the time of this discussion, but dry sub cloud layer should keep most dry through daybreak.
Warmer today with a boundary lifting north through the area, as well as mixing into warmer air aloft. Highs in the mid 80s to lower 90s which is roughly 15-20 degrees above average. A couple of sites may approach records for highs - Sioux Falls (90 in 1897) and Mitchell (92 in 2024) will both be within a couple of degrees of record. These warm temperatures along with breezy southerly winds may lead to some elevated fire danger, although humidity values above critical thresholds should keep conditions localized. Strongest winds are expected across south central SD with gusts around 25 mph. Lows tonight fall into the upper 50s and lower 60s.
May see some hazy skies with wildfire smoke in the area. Not expecting much in the way of surface impacts, but could some reductions in air quality. Otherwise, mid and high clouds will be a bit more prevalent today.
TUESDAY-THURSDAY: A couple of waves/vorticity lobes move north through the southwesterly flow aloft through mid week as high pressure aloft stagnates over the Midwest. CAMs are more bullish with shower/sprinkle chances on Tuesday; however, dry soundings lead to lower confidence in occurrence. May see some lower end chances during the overnight and early morning hours Wednesday and Thursday with the LLJ and the timing of the waves. Despite an increase in surface dew points with more southeasterly flow mid week, there remains a lack of a deep moisture layer coupled with a dry sub cloud layer. Will keep precip chances on the lower (< 15%) side for now.
Temperatures remain above normal, with a slightly cooler day Tuesday due to cooler temperatures aloft. Highs in the 80s and lows in the upper 50s to mid 60s. Temperatures may stay elevated enough during the overnight hours to approach a couple of record warm low temperatures. Southerly surface winds remain breezy, especially during peak mixing, with gusts around 25-30 mph. The increase in dew points should help offset the breezy conditions, very warm temperatures, and drying fuels to limit widespread fire concerns. That said, some lower end and localized concerns are possible.
FRIDAY-SUNDAY: Mid/upper level high pressure flattens toward the end of the week with troughing over the western CONUS moving east through the weekend. Surface low moves east during this time as well. Precipitation chances may return as early as Friday, but better chances look to be Saturday onward with a stronger low pressure and mid/upper level wave. That said, guidance is still quite varied on the details. Ensemble probabilities are trending upward, toward 50%, but uncertainty remains.
As for temperatures, well above average temperatures continue through at least Friday as we remain ahead of the cold front. Near records are possible for both high temperatures and warm low temperatures with highs in the 80s to near 90 and lows in the 60s. Cooler, but still above average, conditions move in by Sunday with highs in the 70s and lows in the 50s.
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.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/... Issued at 1141 AM CDT Mon Sep 29 2025
VFR conditions with occasionally gusty southerly winds will persist through the afternoon hours. Southerly winds continue overnight, as a mid-lvl cloud field begins to thicken and move northward from the south. A few sprinkles/showers may develop after 4am, however coverage remains too low to indicate at this time. VFR conditions then continue through Tuesday as mid-high lvl clouds persist.
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.FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None.
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DISCUSSION...SG AVIATION...Dux
NWS FSD Office Area Forecast Discussion