Updated at 7:05pm Monday, September 1st - A late season severe thunderstorm scenario developed across much of the Pembina and Red River Valleys Labour Day Monday afternoon. Environment Canada issued a Severe Thunderstorm watch for the entire region mid-afternoon, with Severe Thunderstorm Warnings following. As of approximately 7pm Monday evening all Warnings had ended for areas west of the Red River. A Severe Thunderstorm Watch remained in effect for most of Southern Manitoba. For the latest Petro Canada Winkler forecast details, click here. "Our well above average September Long Weekend is coming to a stormy end," explained CMOS Accredited Weathercaster Chris Sumner. "With daytime highs Friday through Monday flirting with 30 degrees, which is about six to seven degrees above average for the end of August and beginning of September, the stage was set for a strong cold front moving through late Monday afternoon and Monday evening to be the trigger and focus for thunderstorm development." Behind the cold front, temperatures will tumble into the mid teens for Tuesday and Wednesday, landing between 15 and 17 degrees. The average daytime high for the start of September is 23 degrees, with an overnight low of 9 degrees. Be sure to check PembinaValleyOnline Tuesday morning for our Rainwatcher reports from this wet end of the weekend.