A very active convective system that came up from Montana, dumped a lot of rain over southern Manitoba Friday morning.

Brian Proctor with Environment Canada says the highest amount reported was in Rosenort where more than 100 millimetres (mm) of rain fell. Yet, 20 kilometres to the southeast, in Morris, less than half that amount was reported. Other readings from around the region include 60 mm in Niverville, 54 mm in Miami, 49 mm in Pilot Mound, 45 mm in Killarney, 40 mm in Carman, 26 mm in St. Pierre, 21 mm in Morden, 19 mm in Steinbach, 17 mm in Marchand, 9 mm in Brandon, 8 mm in Zhoda and 6 mm at the Winnipeg Airport.

Proctor explains the reason some areas received significantly more rain can be attributed to where the strongest updrafts were in those thunderstorms. He notes that is what enables thunderstorms to cycle and take larger and larger particles up into the atmosphere, collecting hail.

"That hail will then melt before it reaches the ground, and so you get heavier precipitation amounts underneath the cells that are being more heavily developed," he says.

Proctor further explains we had an elongated swath of precipitation along a warm front. He adds the localized heavy amounts of rain were where the cells were embedded along the warm front.

While the heaviest amounts of rain in southern Manitoba came along the Canada/ U.S. border, Proctor says there was also a lot of rain in North Dakota where places like Grand Forks experienced overland flooding. He guesses between 50 mm and 100 mm of rain fell in parts of North Dakota. Proctor adds certain areas of the Dakotas and Minnesota also saw large amounts of hail and strong winds. There are no reports of either in Manitoba.

Meanwhile, Proctor says it is shaping up to be an unsettled holiday weekend for weather in southern Manitoba. Winds from the northeast on Friday could cause more thunderstorms in the afternoon and evening hours. Proctor says local rain amounts of 10 to 20 mm are possible. Showers will linger through Saturday and Sunday before things stabilize on Monday.