Say goodbye to summer this week. Ontario's weather forecast is calling for chilly temperatures and thunderstorms across the province. A widespread cool down is expected to bring fall-like weather with temperatures dropping below 20 C.\nAccording to The Weather Network, the much-needed break from the heat is all thanks to an approaching cold front.\nThe cooling temperatures bring the risk for some low-grade thunderstorms and showers. So, you might want to bust out your umbrellas if you're venturing out this week.\nEditor's Choice: A Tornado Watch Has Just Been Issued For Parts Of Ontario\nEnvironment Canada has issued a tornado watch for some areas of the province on Monday including Bruce Peninsula, Sauble Beach and Tobermory.\nScattered thunderstorms are also expected to hit parts of the GTA throughout the evening.\nThose in Toronto can see lows of 14 C at night throughout Monday and Tuesday.\nHowever, the day time highs will rise back up to 33 C by Saturday, so the cool weather won't be sticking around.\nCottage-goers will experience even cooler conditions this week, with Huntsville seeing temperatures drop as low 11 C.\nStill, summer lovers need not worry just yet. Temperatures are expected to rise throughout the province into the end of the week.\n"Beyond Tuesday, these moderate temperatures last a couple more days before a brief warming trend begins at the end of the week and into the start of the weekend, followed by another cold front expected to track across the region," reads a statement by TWN.\nThe Weather Network\n"However, summer is not over – an abundance of summer weather is expected during the month of September," added meteorologist Dr. Doug Gillham.\nOntario has been racked by all kinds of turbulent weather this season.\nA series of heat waves caused daytime temperatures to float around the 40 C mark back in July, and severe thunderstorms have been forecasted on the regular.