Kevin Myatt is The Roanoke Times' weather columnist.

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Here's what summer 2006 has dealt Southwest Virginia so far: It's been a little hot and a little dry, excluding that one soaking week of late June, but nothing really extreme overall.

Looking at Roanoke's temperatures, June averaged about normal in temperature, and July was only a little more than 1 degree above normal.

Thanks to the flooding rains of June 25-27, June was 4 ¹₂ inches above normal for rainfall, making up much of a rainfall deficit that at one time earlier this year approached 10 inches. But July was 2 inches below normal in rainfall, so the rainfall deficit has started building again, and we're 6 inches below normal on rainfall for the year.

That might be hard to believe if you're in one of the areas that has gotten an isolated deluge, like the road-destroying rains in northern Montgomery County on Sunday evening. But since late June, more people in Southwest Virginia are have-nots than haves when it comes to needed rain.

I know that the little creek near where I live that was out of its banks in late June has nothing but dusty rocks in it now. If we hadn't had the late-June downpour, we'd be in deep drought trouble now -- and could yet have flaming fall foliage of the forest fire variety if our rain fortunes don't change soon.

Through Sunday, August started out averaging about 8 degrees above normal in temperature, owing to four straight days of mid- to upper-90s and five consecutive days when Roanoke tied or broke its daily record for warmest low temperature. But this trend is not likely continue.

Forecast models have been bouncing back and forth on whether or not a pronounced jet stream trough will build in the eastern United States.

A jet stream trough is a southern dip that would allow cooler air from Canada to invade, and also bring down periodic cold fronts that could trigger showers and thunderstorms as they cut through the humidity that we've built recently. The hottest weather in the nation would remain in the central and Western states.

This would be an important development, if it comes to fruition, because the new pattern might be long-lasting enough to get us through the rest of summer without another major heat wave. Some sticky days in the 80s, yes, but probably nothing challenging 100.

The forecast models have not been in agreement on this. The Climate Prediction Center's long-range forecast maps have bounced around accordingly, having us in below-normal temperatures one day for the six- to 10-day and eight- to 14-day ranges, and in normal to slightly above normal temperatures the next.

There is nothing at this point to indicate a return of last week's heat wave anytime soon, but if the trough doesn't fully build in, we're in for some more days in the 90s this month. That's nothing unusual for August, though.

Looking further down the road, I'm wondering if autumn 2006 might be different from the warm, humid autumns we've seen recently.

Persistent high pressure in the central and Western U.S., as we've seen most of the spring and summer, would be well-placed with its clockwise spin to circulate some cooler air down from Canada over us as the fall season begins to set in.

Tropical season is a question mark right now. It's far too early to write it off, as the peak of the season won't be for several weeks, and our busy 2004 season didn't have a single named storm until the last day of July. But it's simply not kicking the way many thought it would at this point.

The hot ocean temperatures are there, but upper-level winds have often been too strong, and many would-be hurricanes are sheared apart before they have a chance to develop. Tropical Storm Chris looked likely to become the season's first hurricane last week, but got sheared and then ran smack into Cuba, and is no more.

If the tropical season keeps fizzling and we don't have as much warm, moist air transported northward with tropical systems as we have in previous seasons, we might get the Canadian chill in a little quicker and have a cooler fall than has occurred lately.

That's a lot of speculation at this point. But summer may have already played its ace with last week's heat wave, and autumn will be preparing to show its hand soon.

See the latest tidbits on weather, locally and nationally, on Kevin Myatt's Weather Journal blog at blogs.roanoke.com/weatherjournal/