If you read a range of newspapers you may be convinced that these two things - warming and tornadoes - are strongly linked. Yet there is no convincing scientific evidence that this is the case. This despite the fact that Al Gore included this claim in his Nobel prize / Oscar winning movie - just another unfounded assertion.
The New Scientist reviewed the research and, while thunder storms show some association, they conclude that there is no current evidence. So, the answer is NO (for now).