06/17/2026
⚠️FORECAST UPDATE!
With new data, our confidence continues to increase that the greatest severe weather threat today will be focused a little south than earlier forecasts suggested. A large area of rain and thunderstorms across northern Illinois and northern Indiana may limit how far north the more unstable air can advance. As a result, the corridor for the highest-end severe weather potential has shifted south closer to central and southern Indiana along and near the I-70/74 corridors. As mentioned in our earlier discussions today we have highlighted the importance of the warm front placement, with the most favorable environment expected along and south of that boundary. This is our "fail mode" today if instability becomes limited with a stalled warm front coupled with a rain cooled outflow boundry. This may undercut updrafts and limit an otherwise "high ceiling event".
All severe weather hazards remain on the table this afternoon and evening, including damaging winds, large hail, and tornadoes. The highest tornado risk will likely be near and south of the advancing warm front where storms can remain more isolated before eventually growing into potential broken or segmented line of storm clusters or supercells. Areas across central Indiana, including the Indianapolis region and points south, should continue to monitor updates closely through the evening hours.
Northern Indiana is not completely out of the woods, but the trend over the last several forecast cycles has been for the greatest instability and strongest storm potential to settle farther south than originally expected. The northern risk may still materialize if we can clear this rain and cloud cover out. Today we have a very steep sun angle, and a vigorous low pressure system still capable of rapid destabilization. Rapid destabilization has been noted south of the warm front across the southern half of Illinois.
Bottom line: Watch where the warm front ends up. Locations south of that boundary will have the best chance to see significant severe weather later today and tonight, while areas north of it may remain cooler, more stable, and dominated by rain.
