Storms are usually associated with fronts, especially in warm weather, with cold air fronts collide with warm air, and the upheaval of air produces thunderstorms in advance of the front.
If you hear thunder or see lightning in the distance & you are outdoors, you should really move into a sturdy shelter ASAP. If no house or building is available, then you need to move quickly...
The Polar Front is the general term for the boundary between Arctic air and milder mid-latitude air in the winter. Winter storms do not always form here though.