EDIT: Replaced "argument" by "fallacy"
I keep saying that ocean acidification needs to be the forefront of the argument more. The data is so much clearer and dramatic that it's so much harder to deny the harm being done by greenhouse gases. "It's hot today" is a terrible way to start a discussion with someone who doesn't believe in global warming, just like "it snowed today" is a terrible counter-argument from them.
I don't know about these polar vortexes in particular, but climate change predicts wider swings in both directions, as there is more energy in the system. In other words, the vortex would not have gone as far south if it had had less energy.
If I may share a simpler analog, it's like when I see people on social media mocking flat-earthers and saying, "how do you think cell phones work if satellites aren't real?" Okay - you agree the earth is near-spherical. That's great. But your lack of actual understanding just gave the flat-earthers a chance to point out that cell phones don't actually use orbiting satellites, make you look like you don't know what you're talking about, and win the argument. Now somebody who also doesn't understand is questioning the scientific consensus even more strongly.