3:03 PM EDT Tuesday 21 May 2024 Severe Thunderstorm Watch in effect for: City of Ottawa Conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts, large hail and heavy rain. Hazards: 90 km/h wind gusts Nickel sized hail Rainfall amounts of 30 to 40 mm Timing: This afternoon into this evening. Discussion: Thunderstorms moving through eastern Ontario have the potential to strengthen this afternoon. Should these thunderstorms strengthen, they may be accompanied by strong winds, hail and heavy rain. Large hail can damage property and cause injury. Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles. Heavy downpours can cause flash floods and water pooling on roads. Lightning kills and injures Canadians every year. Remember, when thunder roars, go indoors! Emergency Management Ontario recommends that you take cover immediately if threatening weather approaches. Severe thunderstorm watches are issued when atmospheric conditions are favourable for the development of thunderstorms that could produce one or more of the following: large hail, damaging winds, torrential rainfall. Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@ec.gc.ca or tweet reports using #ONStorm . For more information: ontario.ca/page/be-prepared-emergency .