When Caitlin talks about brain freeze, she refers to it as trigeminal headache. It's actually sphenopalatine neuralgia that causes brain freeze.
A lightning cannot affect people inside a car (or cause it to explode) as depicted since cars behave like a Faraday cage, conducting electricity through outer casing to ground.
At the end, Joe struggles to talk when Weather Wizard tapes his mouth. Joe, however, could at any time simply have removed this tape with his free hand that he used to hold the binoculars.
When Barry and Linda walk through the bowling alley, you can see the bowlers are playing five pin bowling, which is only played in Canada.
As Barry and Joe drive in the car, the door locks can visibly be seen raised up. If the car were actually in real motion (as in the actor really driving and not being towed), the door locks would not be visible.
There seems to be no reason why Barry couldn't have stopped the Weather Wizard from creating the massive storm which formed the tidal wave by using Cisco's Wizard's Wand.