MCV - What's that?
Meteorology is full of acronyms because nobody, including meteorologists, want to go around saying things like mesoscale convective vortex (MCV) all of the time. Unless of course you are trying to impress someone else with your extensive vocabulary knowing full well they probably have no idea what you are talking about. Remember the scene in the bar from the movie Good Will Hunting? It wasn't so impressive when somebody else smarter came along was it? With that said, MCV's can often produce extreme weather from flash flooding tornadoes. So, what exactly is an MCV anyway?
The best way I know to describe an MCV is to say that it is a small scale low pressure center produced by convection. By small scale, I mean typically on the order of 10 to 60 miles wide. These little circulations can wreak havoc on life and property. As a matter of fact they have done so a number of times here in Oklahoma. The reintensification of Tropical Storm Erin in Oklahoma on August 19, 2007 is an excellent example in my opinion. A tropical system that was weakening suddenly intensified overnight in southwest Oklahoma and went on to produce deadly flash flooding and extreme winds in Oklahoma. A powerful low-level jet developed that night which resulted in increasing moisture and powerful thunderstorms with the system. The energy a tropical storm normally gets from the warm water was supplied by the latent heat release in the thunderstorms that developed. The system intensified, even though it was on a relatively small scale, because of convection which is why I believe it was a very powerful MCV.
So, if we know MCV's exist and are a key ingredient in producing extreme weather, why can't we forecast them better? One of the biggest problems in forecasting MCV's is forecasting storms to form in the first place. Remember, since they are convectively induced, (produced by storms) and the atmosphere must first generate storms to begin with. Even then, we have storms all of that time that do not organize enough to produce an MCV. So, just getting the proper foundation for an MCV forecast properly is no small chore. If it weren't enough to be unable to know exactly when or where they will form, we also have to know which direction and how fast they will move. I'm starting to get a headache just thinking about it! Rest assured, when I see a MCV on radar I pay close attention. An event like Tropical Storm Erin leaves a mark on us too.