This transcript was edited for brevity and clarity
Bill Burton: It's time for us to take a look at the Science Behind the Forecast as I'm joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.
Tawana Andrew: Good morning. Today, we're talking about something that, on the global scale of things, is tiny but mighty.
BB: Known briefly as MCS. It's got a bit of a longer title than that, though. Explain to us what MCS is, please.
TA: So an MCS is a Mesoscale Convective System, but as a meteorologist, you will probably hear us use the term MCS pretty often, especially in the summer months.
BB: Good call.
TA: It's a lot easier to say. They are a complex of thunderstorms that becomes more organized than the original cluster of individual storms, and they can last for several hours. So we see them a little bit more often during the summer months.
They typically form overnight as afternoon thunderstorms, or what's left of afternoon thunderstorms, merge into those larger clumps or complexes of storms. And the reason that we see them lasting a little bit more overnight is because we have the warm nighttime temperatures in the summer, and that could help to continue to fuel those storms at that time of the year. So an MCS can be as wide or as long as a state and last for more than 12 hours.
BB: That’s massive!
TA: A lot of them end up being around the size of Ohio, in some cases, as they push across the country. They can be pretty large systems. And in many situations, a low level jet, so that lower level, strong wind flow can help to sustain Mesoscale Convective Systems as they travel for hundreds of miles, in some cases.
With these, the main severe threats that we'll get are usually damaging winds or heavy rainfall, but in some isolated cases, you can end up with hail or on the leading edge of everything, even a tornado. But it's mainly the damaging winds and mainly the heavy rainfall. But those damaging winds, I don't want to discount that at all, because they can be as strong as a hurricane. So in some of these storms you can get 74-plus mile per hour wind gusts, which is definitely nothing to bark at.
BB: No, that's pretty serious.
TA: That can be incredibly dangerous. And there are a couple of types of MCSs. The one that we talk a lot more about is a Mesoscale Convective Complex, or an MCC. And these are commonly recognized by their more round appearance on satellite images. And to qualify as an MCC, the National Weather Service has some pretty strict criteria. A storm cluster must have cloud-top temperatures of 25.6 degrees Fahrenheit or lower, and cover an area of at least 38,000 square miles. Or if the cloud-top temperatures reach -61.6 degrees Fahrenheit or colder, then the area must be at least 19,000 square miles.
BB: Wow, that's all incredibly specific.
TA: Yes, very specific, and they have to keep those specific criteria for a minimum of six hours. There are a lot of MCCs that are initially classified by what we see on satellite, and then they're confirmed later on, after that six-hour time frame has passed.
BB: That is amazing. That's a lot of information to try to absorb, but now we have a better understanding — well, some of us have a better understanding. I'm thoroughly confused, but I enjoyed it. It's the latest edition of Science Behind the Forecast with WAVE 3 meteorologist Tawana Andrew. Thanks for the knowledge. Tawana.
TA: Of course.
