Today's live blog covers the extensive severe weather threat stretching from the Plains to the Ohio Valley.

Severe storms are forecast for Monday afternoon and evening due to a large spring storm system. With two air masses, a warm and a cold one, battling it out, the collision will cause severe weather to erupt, especially from Dallas and Oklahoma City to St. Louis and Cincinnati, Ohio.

Multiple severe thunderstorm and tornado watches have been issued for this evening across the southern Plains and Midwest. Have multiple ways to receive weather warnings, keep an eye on your local forecast, and stay weather-aware.

The line of storm activity is beginning to form in Texas and Oklahoma, as seen on the WeatherRadar. This is getting close to prime afternoon commute time. To reiterate the storm threats, large hail greater than 2 inches in size is posible, significant tornaoes, dmaaging gusts greater than 75 mph, and heavy downpours are all on the table too.

Storm activity is beginning across the Midwest this afternoon from eastern Kansas to Illinois. Watch the storms form on the WeatherRadar and mind the lightning.

We will see more of a storm line form shortly west of Oklahoma City and west of Wichita Falls, Texas, this afternoon, before the afternoon commute. Be sure to have at least three ways to receive a weather warning and check the WeatherRadar BEFORE you get on the roadways to know what's ahead.

Finally, a moderate risk has been added for tomorrow's severe weather threat across the Ohio Valley. We expect more tornado and large hail threats for the second day in a row.

The severe weather threat has been upgraded to as much as a moderate risk due to the large hail threat in the southern Plains. Wichita Falls, Texas, and Oklahoma City and Tulsa, Okla., are all within the moderate risk - more than 33,000 residents.

An important reminder when it comes to tornado and severe weather safety in general... never take shelter under bridges or overpasses. Strong winds and tornadoes can easily suck objects out from under these, including cars and people.

Always check the WeatherRadar before you hit the road to avoid finding yourself in a severe thunderstorm. If needed, shelter in a nearby sturdy building at the lowest level or find a ditch to lay flat in.

These severe storms mean business today and tomorrow bringing all threats to the table; significant tornadoes, 2" hail, 75 mph gusts, and even up to 4 inches of rainfall.

Isolated, non-severe storms are already firing in the Plains and lower Ohio Valley Monday morning, but things will kick into gear in the early afternoon hours, local time, as temperatures rise.

As much as an enhanced risk for severe storms, a level 3 out of 5, has been issued ahead of today's severe storm threat. Weather & Radar will have their Task Force activated to cover the latest details.

Additionally, dangerous flooding is possible with the downpours coming with the storm system. Remember, turn around, don't drown. Have at least 3 ways of receiving a weather warning and your app alerts switched on to get the latest.