Snow potential the next few days

Two storm systems, one weak one and one more substantial, will move through the South between now and Saturday. With colder air moving in from the north, there will be some concern for snow. It's still too early and uncertain to start saying exactly where and how much for the second storm, but the first likely just causes some light snow from Kentucky to Delmarva on Thursday into Friday.

One thing that I didn't cover in the video that I wanted to (ran out of time, had to get away to do a radio live report) is that it looks as though there is some potential for severe storms in Florida on Saturday. Below is the GFS Energy-Helicity Index forecast for Saturday afternoon.

This combines CAPE, a measure of instability, and helicity, a measure of shear, to produce an index to assess severe storm and tornado potential. In a few areas, the EHI reaches 1, which is where you start to become concerned for severe storms. The other models that seem to be handling this storm system look warmer and more unstable across the peninsula than the GFS does, also with a farther north track of the surface low, and if that is correct, then there is an even greater chance for severe storms than the GFS hints at. So, this is something we'll have to keep an eye on. Severe storms or not, we should see a decent rain event down there in Florida on Saturday and that's good because it has been pretty dry.

There's one other thing I wanted to show off today:

This sort of illustrates the reason why most professional meteorologists don't share model snowfall forecast plots for storms way out in advance, at least not any more. Notice the huge amount of change that we have seen from the GFS just over the last 8 model runs going through the 18Z Tuesday model run. The model has been all over the place! For example, it's gone from calling for nearly no snow in Charlotte to over a foot to nearly no snow again to a couple of inches. So, this, and really any other model graphics that someone will post, just needs a lot of context. That's really hard to do on Twitter when you only get 140 characters.

But some people have been posting this stuff (and worse ... much worse), the weather community on Twitter has been in the usual frenzy about it. Hopefully we meteorologists can keep the damage caused by those who post basic model images and ridiculous hype-casts in check and hopefully we can also keep from going from each other's jugular when we disagree with one another. Either way, let me give y'all a reminder that you need to know who you're getting your weather from. If it's me, the others here at AccuWeather.com, your friendly neighborhood meteorologist on TV, or one of our distinguished competitors out there, we deserve and are honored to have your trust. But if your 'meteorologist' isn't even willing to tell you his or her name, I think that tells you exactly how much stock you should put in that person's forecast.

When I say that, I don't want to discourage those who aspire to become meteorologists from starting to hone their skills by putting out a forecast. There isn't a thing wrong with that, just be honest about who you are and what you're doing, and preferably link to other reputable forecast sources for comparison. Similar words apply to those who are self-trained and don't have a meteorology degree. There are plenty of good self-trained forecasters out there. Just be sure you know who your forecaster is before you like and share something on social media so that you don't become part of the problem that comes from spreading nonsense forecasts around.

On social media, y'all can find me as @AccuFrank on Twitter, which is the most reliable way to get alerted when I post new stuff. There's also my Facebook fan page and G+. By the way, I usually have a list of interesting links below the video, if you never have looked down there. Scroll down and check them out!

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