How do two fronts form at low pressure area? Which would bring the most severe weather?

Answer 1

The area around the center of circulation is where usually the stronger storms are located (just look at a hurricane). The East (right) side of the Low usually is the warm front, and the West (left) and South (bottom) is usually the cold front. As warm air is being pushed up from the south, Warm Gulf moisture fuels the storms and where this area meets creates a major clash, and unstable air is created.

Think of it like this, when a drop of water drops and lands on the floor it produces a splatter effect. The floor is where both fronts met and where unstable air is produced. Because unstable air rises, this is where the higher cloud tops are at AND usually the stronger the storms.

Answer 2

Good question but you are ahead of yourself. First the low pressure area forms and this creates the two fronts. Two high pressure domes of differing air properties will have a stationary boundary separating them. This is because air of different makeups do not mix, that is warm dry air does not mix with cold moist air. A wave will develop along this boundary (the cause is complicated) and start a swirling mass of air, this is the low pressure area. Say at the original boundary the cold moist air is to the north and the warm dry air is to the south, this is normal. At the wave center is the low and the cold air is now advancing to the southeast and lifting the warm air and to the east of the low the warm air is advancing over the cold air. You now have two fronts. The cold front in almost all cases will produce the most severe weather, most wind, and heaviest rainfall, but not necessarily the most rainfall. The warm front side of this low pressure generally will have the least severe weather but can have the most amount of rainfall. This is because the warm front moves slower and produces rain over a longer period of time.