On Tuesday, April 29, 2025, Environment Canada issued a severe thunderstorm watch for Ottawa, warning residents to prepare for potentially dangerous weather conditions. The watch is in effect from early afternoon into the early evening, as forecasts predict thunderstorms capable of producing damaging wind gusts and large hail.
According to a notice from Environment Canada, conditions are favorable for the development of severe thunderstorms, with damaging wind gusts expected to reach up to 110 km/h. Additionally, large hail measuring up to four centimeters could pose risks to property and personal safety. "Large hail can damage property and cause injury. Very strong wind gusts can damage buildings, down trees, and blow large vehicles off the road," the notice states.
As the day progresses, residents are advised to take cover immediately if threatening weather approaches, as there is no safe place outside during a thunderstorm. Emergency Management Ontario echoes this sentiment, urging the public to stay indoors when thunderstorms strike. The organization also encourages individuals to monitor alerts and forecasts issued by Environment Canada for the latest updates.
This severe weather warning comes on a day that began with relatively mild conditions. As of 7:00 AM EDT, the temperature at the Ottawa Macdonald-Cartier International Airport was recorded at 14.7°C, with mostly cloudy skies and winds from the south at 23 km/h. However, as the day progresses, the forecast indicates a shift in weather patterns, with a 30% chance of showers in the morning escalating to a 70% chance of showers or thunderstorms in the afternoon.
"Mother Nature seems to love a little drama," noted a local meteorologist, highlighting the unpredictability of Ottawa's climate. The winds are expected to ramp up to 30 km/h, gusting to 50 km/h, while the day's high is anticipated to soar to 23°C, feeling more like 27°C with the humidex. The UV index is moderate at 5, prompting residents to apply sunscreen even as they prepare for potential rain.
As evening approaches, the weather is expected to take a sharp turn. A 60% chance of showers is predicted, along with a continued risk of thunderstorms. Winds will shift from southwest to northwest at 30 km/h, still gusting to 50 km/h after midnight. The temperature will plummet to -2°C, with wind chills making it feel like a frigid -9°C overnight.
Looking ahead, Wednesday, April 30, is forecasted to start brisk but beautiful, with skies clearing by late morning. The high for the day will reach a more seasonable 12°C, and the UV index will drop to a very low 1. By Thursday, May 1, the forecast remains cloudy with a high of 15°C, followed by showers arriving Thursday night with a low around 11°C. Friday continues the trend of unsettled weather, with more showers expected and a high of 16°C.
Historically, April 29 has seen a wide range of temperatures in Ottawa. The record high for this date is a balmy 29.4°C, set in 1942, while the record low stands at a frosty -4.4°C, logged in 2002. Today's high of 23°C places it comfortably on the warmer side of history, but residents are reminded that winter's chill is never far behind.
As the severe thunderstorm watch remains in effect, residents are urged to stay informed and prepared for rapidly changing weather conditions. The unpredictable nature of Ottawa’s climate, often described as experiencing "four seasons in a day," is particularly evident today.
In light of the severe weather warnings, individuals are reminded to take precautions when traveling or commuting, especially on campus where operations continue as scheduled. The university remains open, but safety is paramount. Students, faculty, and staff are encouraged to monitor the university's weather page for updates as the situation evolves.
As the day unfolds, it’s crucial to remain vigilant. Reports of severe weather can be communicated to authorities via email at [email protected] or by posting updates on social media using the hashtag #ONStorm. The community’s safety depends on staying informed and prepared, especially as the threat of severe thunderstorms looms over the Ottawa Valley this afternoon.
