600 FXUS63 KFSD 230353 AFDFSDArea Forecast Discussion National Weather Service Sioux Falls SD 1053 PM CDT Mon Sep 22 2025
.KEY MESSAGES...
- Scattered thunderstorms possible late this afternoon into the early overnight hours. Ping pong ball-sized hail and wind gusts to 60 mph are the main threats from the strongest storms.
- A persistent seasonally warm pattern will be in place Tuesday through early next week with very small chances for precipitation.
- Patchy fog possible on Tuesday morning.
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.DISCUSSION... Issued at 206 PM CDT Mon Sep 22 2025
The tail end of an exiting wave will bring a small chance for some diurnally driven thunderstorms into parts of northwest IA late this afternoon into the evening. With close to 2000 J/kg CAPE in this environment and fairly weak shear, a few severe storms will be possible. The main threats from the strongest storms would be ping pong ball-sized hail and wind gusts to 60 mph. During the evening and night-time hours a wave will move through NE and another shot for storms along the NE/SD border towards Sioux City. These storms may also produce a few stronger updrafts with weak shear and about 1500 J/kg CAPE.
Once the thunderstorm threat passes tonight a ridge of high pressure will settle into northern and central SD. This will bring some cooler morning readings with at least a small chance of a few locations sneaking into the upper 40s near highway 14. With a marginally moist ground in places and light winds, some patchy fog will again be possible, with the better chances near and north of I-90.
Cooler high pressure builds south and brings about a seasonally warm day on Tuesday with relatively light winds. A small corridor around highway 81 and I-29 may see some spotty diurnally driven showers Tuesday afternoon. Skinny CAPE with values less than about 300 J/kg. Fairly low confidence in this occurrence.
A dry and warm pattern develops Wednesday into the weekend with very little if any chance for precipitation. One stronger wave does move by to the north on Friday and brings a nice warm nose into the area, so a very small chance for a shower or thunderstorm on Friday. With this warm nose Friday, should also prove to be the warmest with some mid and possibly upper 80s for highs. Another warm nose may sneak into the area Sunday night into Monday and bring another very small chance, but once again too low to mention. Outside of Friday, Wednesday through early next week should see highs in the 70s to lower 80s.
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.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1052 PM CDT Mon Sep 22 2025
VFR conditions across the region currently. There is a low chance that showers may redevelop into the southern portions of our region over the next few hours. Have included a Prob30 group for showers between 23.06-23.09Z.
Winds become light and variable overnight allowing for patchy dense fog development. As a result, a brief period of MVFR ceilings and visibilities is possible toward dawn and may linger into the mid- morning. Winds remain light with mostly clear skies for the remainder of the period.
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.FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None.
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DISCUSSION...05 AVIATION...AJP
NWS FSD Office Area Forecast Discussion