The whole country is in a La Nina weather pattern right now. El Nino and La Nina weather patterns have a bigger and more obvious effect on the weather than Global Warming does.
If you look at a chart of world wide temperature averages you can see the gradual climb of global temperature averages. You'll also see that there are whole down decades during a global warming but the average is still going up. it's not so much the top of the temp ranges that are really the problem either, it's the bottom temps rising that cause the biggest problems.
The main two things you need to know about weather are, warmer air holds more moisture (up to a point) and hot and cold don't mix. As the arctic air breaks up in the spring and slides south it pushes warm air in front of it. That creates the rising colums of warm air and causes the moisture to start condensing and kicks off thunderstorms.