textproduct: Sioux Falls

KEY MESSAGES

- Scattered convective showers and isolated thunderstorms likely to develop this afternoon and linger overnight. Severe storms not expected, but a few wind gusts to 30+ mph and small hail may be possible. Scattered sprinkles to isolated thunderstorms possible again Thursday.

- Patchy to areas of frost may be possible Friday and Saturday morning. Temperatures will be highly dependent on cloud cover both nights.

- Temperatures will warm above normal by the upcoming weekend into early next week.

DISCUSSION

Issued at 104 PM CDT Wed Apr 29 2026

THIS AFTERNOON: Diurnal CU already forming early this afternoon, which could eventually lead to a few sprinkles over NW Iowa and SW Minnesota. An additional area of weak warm advection aloft has developed high based showers and isolated thunderstorms along the James River. However, more focus for showers and isolated storms will arrive later this afternoon and continue into the evening as a shortwave slides southeast. Soundings show 100-500 J/KG MLCAPE through the afternoon and evening hours, suggesting a few thunderstorms develop. Steep low-lvl lapse rates could promote the transport of 30-40 mph gusts in any stronger shower. Would also not be surprised to see some small hail especially west of the James River.

TONIGHT: CAMS all hint that synoptically drive showers may continue to move southeast through the overnight hours. More clustering of showers may develop around a compact area of vorticity tracking through the Tri-State area. Have increased PoPs as a result of reasonable modeling of this potential. Temperatures will fall overnight, but cloud cover will pose the greatest hindrance to any widespread frost or freeze conditions.

THURSDAY-FRIDAY: The second in a series of three shortwave rotating around a broad upper trough will arrive on Thursday. Similar to today, we'll see rapid destabilization ahead of the wave leading to scattered showers and isolated thunderstorms in the afternoon and early evening. Low-lvl temps are even a bit cooler than today, so some graupel could be possible. The third and final wave rotating through the region is progged to move into the region early Friday morning. This wave could hold onto enough low-mid lvl cloud cover to keep temperatures from falling below freezing, though with light winds any break in clouds may result in frost to near freeze conditions. Cooler northerly flow under surface high pressure will lead to quiet weather on Friday. Though again, afternoon CU will likely fill the sky. Highs remain in the middle to upper 50s.

SATURDAY-SUNDAY: As we've been discussing the past days, we'll begin to see warmer temperatures arrive this weekend, but remain in a pattern that suggests a frontal boundary sliding through the region every 1-2 days. This results in a great Saturday, with southwesterly surface winds and highs in the middle to upper 60s. Model clustering supports the passage of a cold front early on Sunday. High temperatures once suggested to be in the upper 70s a few days ago, will likely only reach into the middle to upper 60s. The passage of this front may not result in any more than sprinkles early Sunday morning.

MONDAY-TUESDAY: This aforementioned pattern continues into the middle of the week suggesting temperatures remain near to slightly above normal, with precipitation chances surrounding a frontal passage late Tuesday growing to near 30 percent in LREF and NBM guidance.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1215 PM CDT Wed Apr 29 2026

Scattered CU field continues to build this afternoon, with a weak wing of warm advection in the James River Valley currently producing light showers.

VFR showers and isolated thunderstorms will be possible into the overnight hours. While severe storms aren't expected, a few 30-40 mph wind gusts could be possible.

Eventually the wave responsible for this activity will move southeast of the Tri-State area after 2am, leaving higher clouds in place. Winds remain light and variable into Thursday.

FSD WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None. IA...None. NE...None.