Severe Thunderstorm Watch Issued Today for the Midwest: Expect Damaging Winds and Large Hail

A fast-moving spring cold front is triggering a severe thunderstorm watch from the lower Great Lakes to the upper Midwest this afternoon and evening. Environment Canada placed portions of Southwestern Ontario, including London, under a severe thunderstorm watch early this afternoon. South of the border, the National Weather Service Storm Prediction Center upgraded much of Southeast Michigan to a slight risk for severe storms, warning that large hail, 60-mph gusts and an isolated tornado cannot be ruled out. What areas are at risk • Southern Ontario: London–Sarnia corridor and surrounding counties • Southeast Michigan: Detroit, Ann Arbor, Flint and suburbs • Northern Ohio and northwest Pennsylvania: threat grows toward sunset • Western New York and parts of Indiana may be added if storms accelerate eastward Timing you need to know • 2-4 p.m. ET – Storms bubble along the Michigan–Ontario border • 4-8 p.m. – Highest severity window; supercells possible ahead of the cold front • 8-11 p.m. – Line races east, transitioning to heavy rain and frequent lightning Remember: a watch means conditions are favorable; a warning will be issued if dangerous weather is imminent. Main hazards 1. Damaging straight-line winds exceeding 95 km/h (60 mph) 2. Hail up to golf-ball size that can dent vehicles and shatter glass 3. Brief, fast-moving tornadoes, especially where storm cells remain discrete 4. Cloud-to-ground lightning capable of striking well ahead of rainfall How to prepare right now • Secure patio furniture, trampolines and garbage bins. • Charge phones and portable power banks in case of outages. • Park vehicles in garages or under sturdy shelters to avoid hail damage. • Identify your lowest, most interior room; have helmets and shoes ready for each family member. • Keep local TV, radio or weather apps on with volume up; enable Wireless Emergency Alerts. Travel and event impacts Late-day commuters on Highway 401, I-94 and I-75 should expect sudden visibility drops and ponding. Outdoor events and Little League practices may need to be postponed; lightning can strike up to 16 km (10 mi) from the storm core. When the watch is lifted The front will sweep cooler, drier air into the region by dawn Friday, ending the severe threat but ushering in windy, 5–8 °C (10–15 °F) lower temperatures. Check roofs, siding and vehicles Friday morning for hail or wind damage and photograph any losses for insurance claims. Stay weather-aware Follow Environment Canada, your local National Weather Service office and trusted media outlets for rapid updates. A smartphone, NOAA/Weatheradio receiver and a backup power source remain your best defense against spring’s most unpredictable storms. Bottom line: Have a sturdy shelter plan, stay connected, and act immediately if a warning is issued—today’s storms pack enough punch to turn routine afternoon plans into a life-threatening situation within minutes.