Kevin Myatt is The Roanoke Times' weather columnist.

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In the ongoing weather regime, the mid-Atlantic region is the graveyard of cold fronts.

Fronts moving out of Canada just don’t make it much farther south than Virginia or, at best, the Carolinas. They simply stall and wash out. Each front might bring a little additional instability for a few more thunderstorms, but really does little or nothing with the mugginess that has pretty much camped itself over us.

Welcome to the “dog days” of August.

It’s really not an unusual weather pattern, it’s just a bit more pronounced this year than it has been in some recent summers. Our weather is being controlled by subtropical high pressure, its main center shifting some from Bermuda to the Gulf of Mexico, but never entirely relinquishing its hold on us. Underneath this high, we’re trapped in a warm-to-hot, humid air mass.

Cold fronts need strong upper atmospheric dynamics -- i.e. winds -- to push them through this muck. The strong jet dynamics have stayed in Canada pretty much since the middle of June. It’s not unusual for the jet stream to vacation in Canada during August, but it’s been really far north this year.

Until these strong upper air winds begin migrating southward, not much is going to happen to pry this stagnant weather pattern loose. The jet stream pushes cold fronts more east than south, and the southern ends get stuck, become diffuse and die right over our heads. One over the weekend did this, and probably another will later this week. Even the strong cold front that broke our 3-day heat wave a couple of weeks back made it no farther than North Carolina.

We have enough heating and moisture for some strong, even briefly severe, thunderstorms from time to time -- but only if you’re very near where such a storm develops. The storms rise in one spot on hot, humid afternoon updrafts, and then blast downward near that same spot, blowing themselves out with one might blast of fury. There are no strong upper level winds to move the storms around, or to enable to develop characteristics that would separate their updrafts and downdrafts to keep them living longer. These storms are all updraft, then all downdraft, then they’re gone.

We’ve talked about them before here -- pulse thunderstorms. The mountains add a little more lift to get some of these going, and also, any fragments of another cold front that’s come to die here.

It’s not that these pulse storms can’t be impressive. Some areas near Radford got rocked by tree-breaking blasts of wind on Friday; some areas near Lexington got the same on Saturday evening. If your house is located near where one of these pulse storms exhales its powerful last breath, you may be cleaning up some tree limbs, or even lose power for a while. If not, you may hear a few rumbles of thunder while the sun keeps shining and not get a single sprinkle.

There are still some atmospheric wrinkles that can help trigger extra rain. A weak low pressure area moving along the Gulf of Mexico is doing that now. It’s pulling in a bit more moisture and providing some instability to squeeze out some rain and thunderstorms around, and maybe quite heavy rain in a few spots.

And we still have to watch the tropics for those prodigious rainmakers that also spin out mighty winds. We’ve reached the “I” storm, Irene, faster than ever in the Atlantic -- some years never reach “I.” Tropical Storm Irene, like Harvey before, is likely to be a “fish storm,” staying well out in the Atlantic, but this busy tropical season will likely spin up at least one more hurricane (and probably more) that will threaten the U.S., and possibly take flooding rains and a tornado threat far inland.

But until the fronts start moving through and plowing all the way to the Gulf of Mexico, there’s not going to be much change in our overall weather pattern. Again, this is not unusual for August, though this summer has tended to be a bit more tropically humid than most.

But fall gets closer with every passing day. By the end of the month, the area of cool air around the North Pole will begin expanding southward as the daylight shorts and the sun angle lessens, and the fast jet stream dynamics will be pushed ever farther south. Gradually, more and more vigorous cold fronts will be pressed farther and farther south, until cool air from Canada and the pole begins invading the United States.

This is the march of autumn against summer. Though its speed, duration and strength vary year to year, this southward march of cooler air in the Northern Hemisphere is inevitable so long as the Earth’s axis is on a 23.5-degree tilt and the Earth keeps revolving around the sun.

So, as sure as the sun will rise, fall can’t be too far away.