Week ahead to warm but also turn stormy

The cold pattern that has held temperatures in the metro area below 50° for nearly two weeks is expected to persist through Tuesday. A shift to a southwesterly jet stream flow aloft midweek will allow the rapid penetration north of warmer temperatures. However the shift in upper-level winds signals the approach of a strong low pressure system that will first hit the west coast, especially California, hard Tuesday, cross the Rockies Wednesday and approach the western Great Lakes Thursday. Not only warmer but much more moist air will flow into the middle Mississippi and Ohio River Valleys spreading an extensive shield of cloudiness along with showers and t-storms. A large portion of the country from Texas and the Gulf Coast north to and beyond the Ohio River will likely experience severe storms. Clouds and rainfall may hold highest readings here in the 50s. This could be the first March since 2002 Chicago fails to record a 70° high.