The Plains and Mississippi Valley will once again be in the crosshairs of a major weather system that will bring a renewed threat for destructive tornadoes, very large hail and damaging winds. Michigan to Texas will be at risk for these menacing storms. Just like Sunday, the threat for significant severe weather is so high the government`s Storm Prediction Center has issued a Moderate Risk for several tornadoes, some of which will be long-lived and strong, destructive wind gusts peaking at 80 mph, and hail greater than baseball size. Cities in this zone of increased danger include Oklahoma City and Tulsa, Okla., Wichita Falls, Texas, Springfield, Mo., and Fayetteville, Ark. Beyond the Moderate Risk area is a broad area of still-powerful thunderstorms that will stretch from the central Texas Plains all the way to the shores of the Great Lakes. Here, wind gusts of 60 to 70 mph, hail to the size of golf balls, and possibly even a few weak tornadoes are possible. This includes major cities such as Dallas, Kansas City, St. Louis, Chicago, Milwaukee, and Detroit. The trigger for today`s dangerous outbreak is a cold front extending from eastern Kansas to southwestern Oklahoma. As the front slowly meanders to the east, much cooler 50s behind the front will collide with much warmer 80s from northern Texas into the Great Lakes. This will set the stage for storms to quickly build across north Texas, central Oklahoma, southeastern Kansas and western Missouri by mid-afternoon. The storms that erupt across the Red River Valley in southern Oklahoma and north Texas have the best opportunity to produce strong, long-tracked tornadoes. Farther north, storms that break out across central Oklahoma into southeastern Kansas will likely organize into line segments with damaging winds, large hail and a few tornadoes. These storms will sweep east-northeast into Missouri and northern Arkansas late this afternoon and early this evening. Even farther north into the Upper Mississippi Valley and western Great Lakes, morning sunshine ahead of the front will allow enough energy to build during the day to ignite thunderstorms by the afternoon. Hail the size of golf balls and damaging winds are the main threats here later today. Beyond the severe threat, heavy rain is likely to make flooding a major concern. Locally heavy rain could total 3 inches or more, particularly across northeastern Oklahoma and southwestern Missouri. A Flash Flood Watch is in place here, with additional Flash Flood and Flood Watches across eastern Minnesota. If you come across a flooded roadway, do not attempt to cross it, as it is likely deeper than it appears. It`s best to "Turn Around, Don`t Drown." The severe threat won`t end today, unfortunately. Instead it will move slightly farther east on Tuesday as the cold front edges into the Mississippi Valley. Cities in the danger zone Tuesday include Detroit, Indianapolis, St. Louis, Little Rock, Ark., and Dallas. The same weather system produced nearly 500 severe weather reports severe weather reports from Oklahoma to Wisconsin on Sunday, including 28 possible tornadoes. One person was killed in Oklahoma when the twister destroyed an entire mobile home park in Shawnee. Three-inch hail was reported Sunday evening in Cedar Vale, Kan., while Andover, Kan., was pummeled by baseball-sized hail. The severe weather ramped up Saturday with 178 severe reports, including a 90 mph gust reported in Nickerson, Kan. Be sure to download the WeatherBug app on your smart phone. The mobile app now includes Spark Lightning Alerts, a GPS-based lightning detection feature providing you the location of the closest lightning strike, so you can Know Before the storm hits. Click here for the link to download. Be sure to keep WeatherBug active to receive the latest severe weather in your neighborhood and get the latest updates anywhere on Twitter. What do you think of this story? Click here for comments or suggestions.