Now that spring is upon us, warmer weather is becoming more prominent. While this is something that many of us have been looking forward to all winter, spring brings us a whole new set of challenges that will only become more numerous in the summertime.

I’m sure you could guess what that is — severe weather season! Get ready to see thunderstorms passing through your local community more often in the very near future. Meteorologists and viewers alike enjoy watching thunderstorms and tend to get enthusiastic about seeing them, but we all know that these thunderstorms could be damaging or life-threatening as well.

You know when these thunderstorms are coming because you hear it from us every 10 minutes, but regarding what we look for so we can inform you of them is something that could be lost in translation during a broadcast. In order for a thunderstorm to form, there are three basic ingredients that are essential, and are what we look for to provide a severe weather forecast. These three ingredients include moisture, rising unstable air, and a lifting mechanism.

Moisture:

A moisture supply is essential, of course. Given that we are in the eastern United Sates, we are closer to a supply of warmer water that is courtesy of the warm ocean currents in the Atlantic Ocean. Evaporation occurs the highest in warm water, meaning a good supply of moisture is transferred into the atmosphere.  We also tend to get a lot of moisture from the Gulf of Mexico.

Rising Unstable Air:

The general idea of air being unstable is that if you push a parcel of air upward, that parcel of air will continue to move up. An unstable air mass contains air at the surface that is warm and moist, while cold, dry air is present higher up. When the atmosphere is unstable, many parcels of air rise upward, which leads these parcels to cool. As a result, any moisture in these parcels of air condenses, and this forms what is called a cumulonimbus cloud. This is your thunderstorm!

A Lifting Mechanism:

Air doesn’t typically rise by itself. As previously said, air needs to be pushed up in order for it to rise when it is unstable. In order for air to get its push, we need what’s called a lifting mechanism, of which there is several in New York state. It’s first important to understand what’s called differential heating. A basic explanation of this is if you have cold air at the surface next to warm air at the surface. The cold air will sink due to gravity, and this will force the warm air up, creating a circulation. This circulation, of which lifting mechanisms contain, transports moisture upward.

— Fronts: The boundary between two different air masses is a front. For example, with a cold front, cold air behind this front cuts underneath warm air ahead of it, and the warm air rises. This rising air will transport moisture upward.

— Outflow boundaries: Thunderstorms often contain cold air that rush out ahead of them, creating “mini” cold front-like boundaries. These will similarly cause warm air ahead of these boundaries to rise and can create more thunderstorms.

— Terrain: This is a simpler concept. When air rushes towards a mountain, for example, moisture within this air is transferred up the mountain and can create thunderstorms.

— Lake Breeze: It’s hard not to mention this one, which is especially relevant to those close to Lake Erie or Lake Ontario. Often times, a lake breeze brings a rush of cooler air from the water into the warmer land air, and this can create rising motion similar to a cold front, or an outflow boundary. The moisture from the lake, combined with the warm land air can rise and trigger thunderstorms.

Thunderstorm formation is a complex process. What’s explained here is just scratching the surface of what the process actually is. In order for meteorologists to learn the process and get our degrees, we had to read many papers and textbooks. Post-school, it is our job to explain this complex information to the viewers in a way that is relevant and easy to understand. In case you wanted to know just a little bit more than we normally tell you, this is a good start!