Just enough warmth and moisture combined with an upper-air impulse moving just to our northwest triggered a few strong to locally severe storms Friday evening with a smattering of high-wind reports — primarily 2 reports of downed trees in both Montgomery and Botetourt counties. There will be some threat of showers and storms until a cold front pushes through Saturday afternoon, though we’ve probably used up most of the instability for stronger storms on Friday evening, and likely won’t recover it before the front moves through. The main threat of severe weather will shift into central and eastern Virginia, where the front may arrive at just the right time to bite into greater daytime heating and more humidity. The weather map at left from the Weather Prediction Center depicts two cold fronts, and second that will arrive late Sunday — an otherwise pleasant Mother’s Day with sunny skies and temperatures rising into the 60s, maybe even scraping 70. It’s behind the second cold front that unseasonably cool, dry air will arrive for a couple of days. That’s where our concern for frost/freeze conditions lies for Monday and Tuesday mornings. The key will be whether the sky clears sufficiently of clouds and the winds die down enough for maximum radiational cooling conditions to develop one or both mornings. If those conditions are realized, Roanoke’s all-time latest freeze date of May 11 could be broken (better chance on Tuesday, May 14), and many locations to the west could land in the mid-upper 20s. Right now, it appears a disturbance moving through Monday might stir up just enough wind and clouds on Monday evening to quell the cooling a little and keep us more in the 30s to near 40 range. A close call on that, and either way, it would be wise to take care of tender outdoor vegetation for each of those mornings. There will almost certainly be some scattered frost, at least.