Severe weather could present a “dangerous situation” tomorrow (Wednesday, June 17, 2026). That’s the assessment of a National Weather Service (NWS) meteorologist who briefed NWS partners this morning.
An outbreak of severe thunderstorms is expected across portions of Illinois and Indiana. Intense tornadoes, swaths of damaging gusts to 80 mph and hail to 2.5 inch diameter are expected tomorrow, according to an outloook that the NOAA NWS Storm Prediction Center (SPC) issued at 2:27 p.m. ET.
Thunderstorms with some risk for damaging winds will pass through Indiana in the late morning and early afternoon, SPC meteorologist Nathan Wendt wrote. SPC expects a more substantial severe threat to develop perhaps by mid afternoon. Large to very-large hail, significant wind gusts, and strong or intense tornadoes will all be possible, according to the outlook.
A meteorlogist from the National Weather Service northern Indiana office who conducted a briefing this morning indicated that a second, more dangerous round of storms could begin in northern Indiana as early as 3 p.m. ET. He said that storm timing is favorable for northern Indiana to receive dangerous storms, which could include powerful, discrete storm cells, vs. the squall lines that are more typical in that area.
In the Tornado Outlook map for tomorrow that the SPC published this afternoon (above), more than half of the state is covered with short, black hatch marks, which indicate a 14% probability that any tornadoes that form will be intense, capabile of producing EF-2 or greater damage on the enhanced Fujita scale. In addition, long diagonal lines cover a large part of northern Indiana, indicating a 9% probability that any tornadoes that form could produce EF-3 or greater damage.
Tornado probabilities tomorrow are unusually high for this time of year in Indiana. The area of the Tornado Outlook map that’s shaded in red, including Knox, Rochester, Rennselaer, Monticello, Logansport, Peru, Delphi, Kokomo, Lafayette, Frankfort and Veedersburg, has a probability of a tornado that’s at least 15%, which is at least 12 times normal.
Tornadoes are not the only threat with tomorrow’s storm system. The above-referenced SPC outlook also indicates that the entire state has an elevated risk of damaging, straight-line thunderstorm winds. Some of these could be intense, with gusts as high as 80 mph. In approximately the northern two-thirds of the state (shaded red in the Severe Wind Outlook map, above), the probability of damaging straight-line winds is at least 4 times normal tomorrow. In addition, short, black hatch marks indicate an area in which, if such severe thunderstorms form, there’s a 10% probability that they will contain winds of 65 to 73 knots (74.8 to 84 mph).
Very large hail is another risk tomorrow. Nearly the entire state has an elevated risk of one-inch hail. In the northern two-thirds of the state (shaded yellow on the Severe Hail Outlook map, above), the probability of such hail is at least 7 times normal. Areas covered on the map by black hatch marks have a 15% probability that any hail that falls will be at least 2 inches wide.
In summary, NWS information indicates that Indiana could have the worst severe weather event in quite a while tomorrow.
Now is the time to make that anyone who will be in Indiana has mutliple, reliable ways to receive weather warnings tomorrow afternoon and even after bedtime tomorrow night.
Hint: sirens are not reliable ways to receive warnings indoors.
If you have smart phone, make sure that wireless emergency alerts for weather are enabled (search the web for your phone model and the phrase “wireless emergency alerts” to learn how). And because intense storms can create cellular data outages, have at least one more alerting method, such as a NOAA Weather Radio receiver or a TV or radio tuned to a local station.
More information about tomorrow’s weather threats will be available tomorrow morning.