Weather Academy: What is a Front?

MONROE, La. (KNOE) - Last week, we learned about pressure systems. Pressure plays a big role in determining our weather, but there are many other factors to consider too. One of those factors would be fronts.

You’ve probably heard meteorologists mention cold fronts and warm fronts quite often, and today we are going to be diving into what exactly a front is and why it can cause such a drastic change to our weather pattern.

At any given time, there are all different types of air masses floating around the earth. These air masses are constantly shifting and moving around the surface of the earth. Each air mass is separated by fronts. A front can be defined as the boundary between different air masses.

So let’s look at a cold air mass first, for example. Along the leading edge of the cold air, mass is where we will find a cold front, aka the front of the air mass. Get it? That’s why it’s called a front. A cold front is this blue line with little triangles along it. The triangles are pointed in the direction that the front is moving. With a warm air mass, a warm front develops along the leading edge. A warm front is shown as a red line with half circles pointing in the direction the front is moving.

Fronts usually move around a low-pressure system. We know that air around a low-pressure system moves in a counter-clockwise direction. Our fronts rotate and eventually collide with one another. Where a cold air mass collides (or converges) with a warm air mass is where we see the cold front. The warm air is less dense than the cold air and is lifted up and over the cold air. As the warm, moist air is lifted, thunderstorms are created. That’s why we usually see active or even severe weather when a strong cold front moves through. Cold fronts also bring dry winds out of the north in their wake, which means lower humidity and clear skies in the days following a frontal passage.

Make sure you tune in next week when Sheena and I will be conducting an experiment to help better illustrate fronts. And if you have any tried out any of our past experiments at home, share your photos and videos with us here!

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