MEMPHIS, TN (WMC) - Although warm weather can play a part in severe weather, it is not the sole factor for storm development.
The ingredients for severe weather make up the acronym SLIM. Shear, Lift, Instability, Moisture.
When temperatures are abnormally high, especially in the winter, you can have an increase in instability and moisture and more lift. However, these factors have to be very high to prime the atmosphere for storms. In addition, you will still be lacking shear, which is essential for tornadoes to form.
Also, there must be cold, dry air above the warm surface air for sufficient lift. If the air is still relatively warm and moisture rich several hundred feet above the surface, the air will never rise high enough to form strong thunderstorms.
The process of forming severe storms is extremely complex and all ingredients have to be perfect for storm development. So, you need more than just warm air to get severe weather.