Nightly News | May 17, 2013
>>> good evening. as we head into this weekend, a powerful weather system with an awful history it left behind in the state of texas is tonight now crawling east. it means a lot of people -- 35 million americans in all -- are living in a region where they need to be watching the skies and aware of thingses in the in the days to come. cutting the eastern third of the country from north to south contains embedded severe weather . we want to begin with weather channel meteorologist mike seidel in granbury, texas, a town demolished by the system two days ago. mike, good evening.
>> reporter: good evening, brian. that system which spawned those tornadoes, that ef-4 wednesday night killing six has moved east it's a weaker system. late this afternoon in northern alabama near athenses a twister on the ground. this is not a big one. it did take out trees and power lines and caused structural damage. the threat level there will be low for the evening into north georgia . but we are expecting the largest severe weather and tornado outbreak of the season. it will last into next week. saturday's forecast, the red area will fire up in the central plains in fairly rural areas . still dangerous. sunday is shaping up to be the most dangerous day of the weekend. the storm shifts east into the populated areas. minneapolis to oklahoma city . the highest threat includes des moines and k.c. and monday the risk of tornadoes including chicago and st. louis. one thing we have been missing through the spring is warm, sticky, tropical air, fuel for the storms. now we have the spin in the atmosphere, the hot sticky air. tonight in granbury, heat indexes at 98 degrees . those are the areas 35 million americans need to be on alert for storms tomorrow through monday.