The jet stream stayed mostly to our north and allowed warm air to come up. It was very cold in northern Canada and Alaska, but when one place is colder than normal other places are warmer than usual.

To get a lot of warm air up here like we did last week, you need a topsy-turvy jet stream . . . really bouncing all over the place.

It got cold in December and stayed cold. Temperatures have been relatively warm since January, with not a lot of fluctuation. We've had a negligible number of potholes to this point. But remember, we've made a lot of improvements to our roads.

When you get those kinds of conditions and you get a jet stream that is moving right into that area, that is exactly what we're looking for in environmental conditions that can produce a ... tornado outbreak like we had yesterday.

Warm air exits through these cavities and exits through the attic.

Out of the south cometh the whirlwind: and cold out of the north.