Day 1 Convective Outlook
Issued: · Valid: –
Summary
Severe thunderstorms capable of producing damaging wind gusts and hail are expected tonight across parts of north-central Illinois into southwest Ohio, the central Plains, and the Intermountain West. The most significant severe wind threat will occur late this evening as a storm line moves through the Midwest.
Product Text
000 ACUS01 KWNS 140102 SWODY1 SPC AC 140100 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Thu Aug 13 2026 Valid 140100Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTH-CENTRAL ILLINOIS INTO SOUTHWEST OHIO... ...SUMMARY... Thunderstorms with severe wind gusts and hail will be possible tonight from parts of north-central Illinois into southwest Ohio. Severe gusts and hail will be possible in parts of the central Plains. A few severe gusts may also occur in parts of the Intermountain West. ...Mid Mississippi and Ohio Valleys/Southern Great Lakes... The latest water vapor imagery shows a mid-level anticyclonic flow pattern over the central U.S., with west-northwesterly flow located over the eastern U.S. At the surface, a quasi-stationary front is analyzed from northeast Missouri to northern Kentucky. Surface dewpoints along and to the south of the front are in the 70s and low 80s F, which is contributing a west-northwest to east-southeast axis of strong instability. The RAP has MLCAPE along this axis in the 3000 to 5000 J/kg range. To the north of the instability axis, short-term model forecasts move a subtle shortwave trough east-southeastward through the Midwest tonight. Large-scale ascent associated with the trough coupled with increasing low-level flow will likely result in the development of a line of strong storms. This is forecast to take place late this evening, with the line moving southeastward from north-central Illinois across central Indiana and into southwest Ohio. Severe wind gusts will be possible with this line segment. ...Central Plains... Southwesterly mid-level flow is currently in place over much of the southwestern and central U.S. An embedded mid-level shortwave trough appears to be moving into the central High Plains. Ahead of this feature, the RAP has an axis of moderate instability located from northern and western Kansas into northeastern Colorado, along which MLCAPE is estimated in the 1500 to 2500 J/kg range. Scattered thunderstorms were ongoing near the instability axis early this evening in eastern Colorado with another cluster in central Kansas. Increasing low-level flow from this evening into the overnight period will likely sustain convective development. Hail and isolated severe wind gusts will be possible with the stronger cells. ...Intermountain West... On water vapor imagery, multiple shortwave troughs appear to be moving through the Intermountain West. Ahead of these features, scattered thunderstorms are ongoing across much of Nevada and Utah. The RAP is currently analyzing an axis of instability from southeast Nevada into north-central Utah along which MLCAPE is estimated to be in the 750 to 1000 J/kg range. Near the instability axis, the RAP also has low to mid-level lapse rates in the 7.5 to 8.5 C/km range. This thermodynamic environment should support an isolated potential for severe wind gusts this evening. ..Broyles.. 08/14/2026 $$