Severe weather potential increasing early next week

 The weekend will be a dry and somewhat pleasant one, but next week will start off on an active note. A strong surface low pressure system will develop to our West and Northwest Monday, eventually drawing a cold front through the area Tuesday morning. Ahead of this front, we will be increasingly warm and windy with a chance for some thunderstorms. Below is a look at the ingredients that would need to come together to form our chance for strong to severe storms.

Multiple ingredients have to come together to form strong or severe storms. Moisture is one of the most important ones. Ahead of the cold front, strong Southerly winds will feed lots of moisture into the Midwest region, raising dew point values into the 60s locally. Paired with temperatures near 80°, Monday will have a humid feel to it.

The moisture will aid to develop a lot of instability across the region as well. This is the atmospheric energy storms feed off of to develop. The highest instability will be primarily West and Southwest of us, but we will see a fair amount of it locally as well.

The main driver for these storms will be the cold front, but also the strong winds just a few thousand feet above the surface. This change in wind speed with height is called shear, which is another ingredient for storms. The strongest winds aloft will arrive Monday evening, perhaps providing the key to our timing of the strongest storms' arrival. Our window to watch for would be during the afternoon with some pre-frontal storms, then during the evening along the main line just ahead of the front.

The Storm Prediction Center continues to expand our severe weather risk for Monday, now spreading the higher risk into portions of Northwestern Illinois. The best ingredients look to form mostly West of the Rockford, but the line of storms will likely track through the area later into the evening. At the moment, my highest concern for any storms would be with damaging winds rather than tornadoes locally. There may not be as much spin in the atmosphere needed to form widespread rotating storms. That said, the threat is still more than a few days out, so be sure to stay weather aware over the coming days as the forecast becomes more refined.