Kevin Myatt is The Roanoke Times' weather columnist.

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Some of you got a heaping helping of hailstones on Thursday afternoon.

The latest in a series of strong cold fronts pushed eastward into a little bit of warm, humid air that had built in at the surface. A weak area of low pressure along the front helped pull up some winds from the south and southeast against this front.

The front was well timed for severe weather in our area, arriving in the afternoon, the time of peak heating. While the approaching front acted to lift warm, moist air upward, the extra heat added even more lift, bubbling moisture into the cold air aloft to fire thunderstorms.

This is where the hail formed. Strong updrafts carried raindrops in the clouds upward to where it was colder, freezing them into hail. The hail kept being lifted into colder air until it was too heavy, then fell to the ground. Hailstones of up to 1 inch in diameter occurred in some thunderstorms Thursday. More common, though, was a heavy shower of smaller stones, covering the ground in some locations.

Hail differs from sleet, the bouncy ice pellets of winter, in how it forms. There are no updrafts involved with sleet; rain falls into a layer of below-freezing temperatures on its way to the surface to create sleet. Hail and sleet both involve denser ice than snow, which crystallizes in the clouds and falls to the ground, requiring temperatures near or below freezing from cloud to ground.

Hail has to be a lot denser than snow to even reach the ground, because typically it is falling through several thousand feet of well-above-freezing air, and much of it melts before hitting the ground. So whatever hailstones you might have seen Thursday were larger in the clouds.

Strong winds out of the west, riding atop lighter surface winds out of the south, gave many of Thursday's thunderstorms a slight twist. When storms rotate, updrafts and downdrafts are moved apart so they don't interfere with each other, allowing the storms to continue strengthening.

As I watched and photographed a severe thunderstorm over the Roanoke Valley just before 4 p.m., I noticed some rapid rotation in the clouds. The cloud base was quite high, so it would have been difficult for this circulation to reach the ground. Also, as I watched one of the pockets of rapid rotation pass almost right overhead, I was suddenly hit by cold winds blowing out of the storm. Typically, in an environment more conducive for tornadoes, a warmer wind would be blowing into the storm, as the circulation inside the storm wrapped up.

So while I wasn't too concerned about tornado danger, there was enough of a spin in this storm to intensify its ability to spit out a large amount of hail not far to my north and unleash some winds strong enough to break a few trees. If it had been a little warmer or more humid, Thursday's severe weather could have been much more than mostly a curiosity, but could have been quite dangerous. The wind dynamics were certainly there to support more widespread severe thunderstorms, or even a few tornadoes.

This is sometimes what happens when fall bumps up against summer, when the tundra fights the tropics in its annual autumnal duel. Unlike the last couple of years, the tundra is winning this time. Go outside early this morning and see how cold it is if you don't believe it.