For the fourth straight day in a row, vicious storms producing destructive tornadoes, very large hail and damaging winds are on the weather menu from the southern Plains to the Great Lakes. This is part of the same storm system that produced a deadly tornado in Moore, Okla., Monday and widespread severe storm reports since Saturday. A Severe Thunderstorm Watch continues across southern Oklahoma and western Arkansas, including Ardmore and McAlester, Okla., and Fort Smith, Ark. Thunderstorms are rolling across central Oklahoma and Arkansas this morning, producing damaging wind gusts and hail the size of quarters. These storms will continue to expand east while fresh severe storms form in their wake later this afternoon. Once again today, the threat is sufficiently high that the Storm Prediction Center has an elevated Moderate Risk for severe weather in northeastern Texas, northern Louisiana, far southeastern Oklahoma and southwestern Arkansas. This heightened threat area includes the Dallas-Fort Worth Metroplex, Waco and Texarkana, Texas, and Shreveport, La. Here, large and powerful tornadoes are likely, along with destructive winds of 70 to 80 mph and hail to the size of baseballs and softballs. Beyond that, a large section of the Central U.S. is at risk for strong to severe thunderstorms, including Austin, Texas, Little Rock, Ark., St. Louis, Chicago, Indianapolis, Toledo, Ohio, and Detroit. Beyond the severe threat, heavy rain is likely to make flooding a major concern. Locally heavy rain could total 3 inches or more. Flash Flood and Flood Watches are in effect across eastern Oklahoma and western Arkansas, as well as northern Minnesota, northwestern Wisconsin and northeastern North Dakota. 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 same cold front that sparked the violent weather Saturday, Sunday and Monday is the root cause for today's expected storm outbreak. The front is lined up from eastern Minnesota to western Oklahoma. As it slowly moves east, warm, humid 80-degree air will clash with cooler, drier weather settling in behind the front to product the storms. Enough spin in the atmosphere will unleash more tornadoes. Fifty-five possible tornadoes have been reported since Saturday, including a massive tornado that spun across Moore, Okla., Monday afternoon killing 91 and injuring hundreds. It has been preliminarily rated at EF-4. Make sure that you 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.