Last weekend was a nice one for outdoor activities in Southwest Virginia. This one looks to follow suit, with lots of sunshine, very warm but not really hot temperatures (upper 70s to mid 80s) as the 1024-millibar or so high depicted at right (that’s 30.24 inches of mercury) on Sunday morning takes control of the weather for the weekend and well into next week. There are just a couple possible bugs. (1) With that kind of warmth and some humidity, you can never entirely rule out an afternoon pop-up shower or storm, especially where terrain assists with upslope flow or differential heating, i.e, the difference in surface warming between mountains and valleys. (2) The weak low-pressure trough near the Atlantic coast, depicted on this map as a dotted line. It’s possible that trough may drift just a bit farther west than this map shows, bringing a chance of scattered showers and storms for late Sunday, especially south and east of Roanoke. Neither of these are huge deals, typical summer stuff, but just keep an eye to the sky and radar in the afternoon to see if anything looks threatening near where you are.
We’ll stay warm to hot — some 90s possible by Tuesday or Wednesday or so — and a bit humid through this week underneath this high. A few afternoon pop-up showers and storms will be possible each day, but beyond whatever effect the coastal trough may have on Monday, there is no organized storm system expected until a cold front approaches by late Thursday or Friday. This will likely signal the start of a significant pattern change, as a “heat dome” high pressure system builds in the West and a corresponding deep trough, or southward dip in the jet stream, digs into the East. Wetter, mostly cooler weather will return by next weekend, which probably won’t be as nice for outdoor stuff as this one.