It's an American truism that school starts later in the north than it does in the south. Some school systems in the southeast began classes yesterday, while most northern schools won't begin until the day after Labor Day. There is nowhere in the country that provides a starker view of this north vs. south "first day of school divide" than Virginia.

Here are all 489 severe weather warnings issued in the past 7 days as of midnight-ish. Severe thunderstorm warnings are blue, tornado warnings are red, flash flood warnings are green. An active couple of days, but still quiet for May. More active weather is expected on Friday in the southeast and southwest.

The cold front is pretty easy to spot in Oklahoma this afternoon — it was 92°F in Tipton while temperatures dropped into the 50s a few counties away. A line of severe thunderstorms is announcing the arrival of the cooler air, bringing temps as cold as the low 20s by tomorrow night.