First severe weather outbreak of 2009 possible in the Southern Plains

A favorable setup for severe weather is expected to develop on Tuesday across the Southern Plains as a powerful upper level disturbance intersects warm and moist air across the middle part of the country. 

Severe thunderstorms, including the threat for tornadoes, will become likely late Tuesday across a large area from Texas northeast to Missouri.  Severe weather is possible as far east as northern Mississippi.  The highest risk for violent thunderstorms exists across southeastern Oklahoma.

This storm system will spread the risk of severe weather across the Tennessee and Ohio Valleys on Wednesday.