Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0250 PM CDT Tue Mar 10 2026 Valid 102000Z - 111200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN/CENTRAL ILLINOIS INTO NORTHWEST INDIANA... ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WEST/CENTRAL TEXAS INTO CENTRAL OKLAHOMA...AND THE MIDWEST INTO THE GREAT LAKES... ...SUMMARY... Scattered to numerous severe thunderstorms are expected today and tonight from the southern Plains to the southern Great Lakes vicinity. All severe hazards are likely, including the risk for multiple strong to intense tornadoes, damaging winds, and very large hail. ...20Z Update... The majority of the forecast remains on track and is unchanged. Modest adjustments were made to the Enhanced risk in the southern Plains. Surface heating is increasing into more of the I-35 corridor as clouds continue to gradually erode from west to east. As mid-level ascent increases into the evening, there is potential for more organized linear structures to move into central Oklahoma and North Texas. Steep mid-level lapse rates sampled by observed soundings and TAMDAR data suggest severe winds would be a concern with these linear structures. Farther north and east, it appears probable that capping will lead to decreasing storm intensity. Additional details are found in the previous discussion. For additional short-term, mesoscale details see MCD 186 and 187. ..Wendt.. 03/10/2026 .PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Mar 10 2026/ ...Midwest/Southern Great Lakes/Ohio Valley... A weak surface low over eastern KS late this morning will translate northeastward along a front towards northern IL through tonight. Low-level warm/moist advection will continue today across the Midwest/OH Valley into the southern Great Lakes, where surface dewpoints of at least low to mid 60s will likely be present by this evening. Large-scale ascent across this region will remain fairly nebulous, as an upper trough ejects eastward over the northern Plains. Still, a strengthening low-level jet across MO into IL/IN from late afternoon into this evening should promote scattered supercell development along/near the front in north-central IL. Moderate to locally strong instability, steep mid-level lapse rates, and strong deep-layer shear will all contribute to a very favorable environment for significant severe potential. Very large hail (2+ inches in diameter) will be possible with initial supercells. Effective SRH and related low-level shear will markedly increase around 11/00Z and later in tandem with the strengthening low-level jet. The supercellular tornado threat is likewise expected to quickly increase through the late afternoon/evening, as enlarged/curved low-level hodographs will easily support intense low-level rotation. A focused corridor along and just south of the front will have the best potential for multiple strong to intense tornadoes (EF2-3+). Accordingly, greater tornado probabilities (15%) and a categorical Moderate Risk have been included across parts of northern/central IL into northwest IN with this update. Convection should eventually grow upscale along/near the front late this evening into the early morning hours on Wednesday. But, the threat for tornadoes and severe/damaging winds will likely continue with eastward extent across the Midwest/OH Valley, as both sufficient instability and strong low-level/deep-layer shear will be present across the warm sector. ...Texas into Oklahoma... A closed mid/upper-level low over northern Mexico will move eastward across the Southwest and southern High Plains by this evening while devolving into an open wave. Enhanced southwesterly flow aloft and pronounced large-scale ascent preceding the upper trough will encourage robust thunderstorm development by mid to late afternoon along the length of a surface dryline extending southward across much of west TX. Steep mid-level lapse rates and strong deep-layer shear will support updraft organization, with an attendant threat for supercells initially. Very large hail (2-3+ inches in diameter) will be possible with this discrete activity, before a transition to more linear structures occurs through the evening. An increase in the severe/damaging wind threat will likely be realized as this mode transition occurs across parts of central TX into southern OK. Some threat for embedded tornadoes will also exist, especially into central TX where greater low-level moisture and shear are forecast. A separate area of severe potential may develop this afternoon/evening across parts of central into northeast TX in the low-level warm advection regime. While weakly forced, there is some chance for at least isolated supercells to develop and pose a risk for large hail and a few tornadoes. This scenario remains uncertain, but 5% tornado probabilities have been expanded eastward to account for this conditional potential. ...Oklahoma/Kansas into the mid Mississippi Valley... A dryline will be in place across western OK today, with a cold front forecast to move slowly southward across KS and parts of MO through tonight. While this area will largely remain between stronger large-scale forcing to both the north and south, it appears probable that additional thunderstorms will eventually develop this evening/tonight along/south of the front. Tornadoes and large hail appear possible with any sustained supercells, while damaging winds should occur with line segments that can develop and spread eastward through early Wednesday morning.Read more
