Typically during thunderstorms most lightning strikes carry a negative

I'm seeing confusion over the phrases "positive charge" and "positive particles" in this argument. The key to clearing up this confusion is to recognize that this argument basically has nothing to do with positives or negatives.

The author argues that smoky areas near forest fires probably have extra positive strikes because the smoke carries positively charged smoke particles into the air. In other words, the presence of positively charged particles (from the smoke) causes extra positive strikes.

Let me put this another way: The author argues that smoky areas near forest fires probably have extra goldfish strikes because the smoke carries groovy smoke particles into the air. In other words, the presence of groovy particles (from the smoke) causes extra goldfish strikes.

I've just substituted complete nonsense into the argument, but the logic is exactly the same: more of a certain kind of particle leads to more of a certain kind of strike. In this case, they happen to be called "positively charged" particles and "positive" strikes. But the argument essentially says that if you add more of X, then you get more of Y.

We don't care about how the actual science of electricity works, and GMAT questions will NEVER test you on your science knowledge. In this case, you only care about undermining the hypothesis that "the extra positive strikes occur because of the presence of such particles in the storm clouds."

I don't feel strongly about this, one way or another. Historically, large test-prep companies have often made a big deal out of this ("read the question first, it's magical!!!"), and I think that's misguided -- if reading the question first helps, it won't help much, and it can't do anything for you on RC, since you can't even see all of the questions.

Personally, I don't read the question first, because I'll ultimately need to have a flawless understanding of both the structure of the passage and the author's language choices. When you read the question first, there's some risk that you'll be so hyped up about looking for something specific (an assumption or a way to strengthen something, or whatever) that you won't read with as much precision as you would otherwise. I don't think that the risk is huge, though. So do whatever works best for you, as long as you're breaking down the structure of the argument with precision.

Remember to stay focused on the exact question we have been asked.

This question asks us to undermine the hypothesis. The hypothesis is that "positively charged smoke particles in an area lead to extra positive lightning strikes in that area." This hypothesis has nothing to do with how powerful a positive lightning strike is. It has to do with how many positive lightning strikes there are.

To clarify the language: if I say that cities have an unusually high proportion of car accidents in August, I don't mean that the car accidents are especially severe in August. I'm just saying that there's a greater number of car accidents in August.

I hope this helps!