THUNDER BAY — It is going to get wet. Environment Canada has issued a Yellow Warning – Rainfall for the City of Thunder Bay, with 30 to 50 mm of rain expected from Thursday evening to Friday evening. Rain may be heavy at times, and the frozen ground has a reduced ability to absorb the incoming rainfall.
Today’s Weather Overview
As of 5:00 PM EDT Wednesday, April 22, Thunder Bay was sitting at 10.8°C under mostly cloudy skies. Winds were from the ESE at 26 km/h, humidity was 35 percent, visibility was 32 km, and pressure was 101.5 kPa and falling.
Conditions remain fairly calm for now, but the weather pattern is shifting. Tonight starts clear, then cloud increases after midnight, followed by showers and a risk of a thunderstorm before morning. Winds will become east at 20 km/h after midnight, with an overnight low of 4°C.
Rainfall Warning Details
Environment Canada says a cold front will push into the area Thursday, bringing showers and a risk of thunderstorms. The rain is expected to continue Thursday into Friday as the front stalls over the region.
The main concern is rainfall of 30 to 50 mm, with water likely to pool on roads and in low-lying areas. Environment Canada is warning drivers not to travel through flooded roadways and to watch for washouts near rivers, creeks, and culverts.
Tomorrow’s Forecast
Thursday, April 23
Thursday begins with showers, which are expected to end late in the morning. After that, Thunder Bay will see a mix of sun and cloud with a 40 percent chance of showers. There is also a risk of a thunderstorm in the morning. Winds will be from the east at 20 km/h gusting to 40, and the high will reach 9°C.
Thursday night is when the warning period becomes more serious. The forecast calls for cloudy skies, a 40 percent chance of showers in the evening, then rain beginning near midnight. There is a risk of a thunderstorm in the evening and overnight, with 15 to 25 mm possible Thursday night alone.
Friday, April 24
Friday brings periods of rain with a high of 8°C. The rain warning remains in effect through Friday evening, meaning road ponding, poor drainage, and localized flooding concerns could continue through the day.
Friday night turns colder and more unsettled, with cloudy skies and a 40 percent chance of flurries or rain showers. The low will be 1°C.
Weekend Outlook
The weekend improves. Saturday is forecast to bring a mix of sun and cloud with a high of 11°C, followed by cloudy periods and a low near 0°C. Sunday also looks decent, with a mix of sun and cloud, a high of 11°C, and cloudy periods Sunday night.
Travel and Local Impact
The biggest issue will be water. With 30 to 50 mm of rain possible and frozen ground limiting absorption, expect ponding on streets, saturated ditches, and water collecting in low-lying areas. Drivers should slow down, leave extra space, and avoid driving through flooded sections of road.
Wardrobe Recommendations
Tonight and Thursday call for a waterproof jacket, water-resistant footwear, and layers. Thursday may not be especially cold, but wind, rain, and damp air will make it feel raw. By Friday night, colder air returns, so keep a warmer jacket handy.
Weather Trivia
Spring rainfall events can be more troublesome than they look in northern Ontario. When the ground is still frozen or only partly thawed, rainfall runs off instead of soaking in. That can turn an ordinary rainy day into a drainage and ponding problem, especially near culverts, creeks, and low-lying roads.
