textproduct: Sioux Falls

KEY MESSAGES

- Diminishing thunderstorms arrive late tonight, and could linger into daybreak Friday. Severe storms not anticipated.

- Outside of a very localized risk for thunderstorms late Friday afternoon over SW Minnesota and the Ridge areas of South Dakota, a dry forecast into next week is anticipated.

- Temperatures through the upcoming 7 days will trend warmer, with widespread highs in the 90s to near 100 through much of next week. 1-2 days may feature heat advisory conditions. The cumulative nature of the heat could lead to heat illness.

DISCUSSION

Issued at 143 PM CDT Thu Jul 9 2026

THIS AFTERNOON: Quiet conditions are likely this afternoon as winds remain light and variable.

TONIGHT: Scattered convection that forms over the western High Plains will begin to roll eastward through the evening hours as a shortwave moves into the region. The majority of instability remains bottled up over the West River areas through the evening, and as convection slides eastward it's likely to diminish quickly by time it reaches the CWA. A few gusty winds with decaying showers could still be possible into south central SD. The remnant area of vorticity may drift into northern Nebraska, and could keep a low risk for convection through daybreak in the MO River valley.

FRIDAY: A secondary area of convection may form over central ND late tonight, and slowly drift into northeastern SD by mid-morning Friday. A potential MCV could linger into Friday afternoon over the SD portions of the Buffalo Ridge, and with that area on the edge of the low-lvl EML, can't rule out isolated to scattered convection forming after 4-5pm. From a parameter perspective, MLCAPE values remain near 2000 J/KG, but effective shear is very weak, suggesting only pulse strong storms with wind and brief hail could be possible into SW Minnesota during the evening. As instability pulls northward in the evening the severe weather risk should diminish quickly. Elsewhere, a breezy southwest wind will push highs into the upper 80s to lower 90s.

THIS WEEKEND: Mid-lvl heights begin to rise quickly as we head into the weekend, which will begin a stead upwards rise in temperatures. One thing to note in recent guidance is that surface winds Saturday and Sunday remain more from the southeast and rather light, which could hold down the extreme climb in highs suggested a few days ago. We'll also see a bit more mix down of dry air as soundings have also trended a bit drier, this will allow afternoon dew points to fall and keep heat index values below critical limits.

MONDAY-THURSDAY: A dry and hot week is expected in the region as a 600+ DM 500 mb ridge centers itself over the CWA. The placement of the ridge prevent any storm development, but allow temperatures to climb through the 90s most days. Confidence is high that we'll see temperatures in the middle to upper 90s in most locations, with some areas reaching 100 along and west of the James River valley. The EC ensemble supports this idea with 60%+ probabilities along the James River valley Monday-Thursday. With afternoon dew points mixing down at least into the upper 50s to lower 60s, this should prevent widespread heat index readings over 100 degrees. While the day to day numbers may not be extreme, the cumulative effect of the heat could lead to health related strain by mid-late week.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1153 AM CDT Thu Jul 9 2026

Diurnal CU field continues to form at mid-day. Brief periods of MVFR ceilings are possible over the upcoming 1-2 hours, but will lift towards VFR levels for the remainder of the afternoon. This cloud layer will dissipate this evening, leaving high level clouds in the area.

Scattered convection moves eastward overnight, likely diminishing in most areas before reaching the TAF locations, however mid-lvl clouds (AOA 10K ft AGL) may develop as mid-lvl moisture/instability arrives. Isolated to scattered showers may linger along or north of Highway 14 into mid-morning. VFR conditions and light winds will prevail elsewhere.

FSD WATCHES/WARNINGS/ADVISORIES

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