UPDATE 5:20 PM: Just isolated showers/storms this evening; recapping some recent windy storms in Roanoke
UPDATE 5:20 PM: Drier air moving in and at the surface has limited storm development today in Southwest Virginia. A few isolated showers and storms have occurred, mainly south and west of Wytheville, but it does appear activity will remain “isolated” rather than “scattered to numerous” for our region today. END UPDATE
Roanoke Regional Airport clocked a 54 mph wind gust Friday when what was at least briefly a “bow echo” storm line barreled through, knocking power out to more than 1,500 in and near the Roanoke Valley, and spreading some ominous clouds while spraying some (not all) with some locally heavy downpours. That 54 mph gust — 4 mph below the thresshold for “severe” winds in a storm– is the third 50-plus thunderstorm gust of this summer — there was a 52 mph gust on July 16 and, of course, the 81 mph derecho peak gust on June 29. Interestingly, the airport clocked three separate severe storm gusts in a 2-week period last summer — 62 mph on June 20, 64 mph on June 28 and 75 mph on July 4. There was also a 52 mph gust in a March 2011 thunderstorm that damaged an apartment complex nearby, and gusts of 53 and 58 mph in storms in August/September of 2010. That’s 9 50-plus storm gusts at Roanoke Regional in 3 years, with 5 qualifying as severe. And that’s not counting gusts of 59 and 62 mph gusts behind cold fronts in February 2010.
We’ll be continuing Saturday with the recent theme of very warm to hot temperatures (80s to low 90s high) and sticky with afternoon thunderstorms, as the cold front that has been moving our way for the last 2 days finally arrives and pushes through. The lift with the front will assist daytime heating, terrain effects and any leftover outflow boundaries from Friday storms in firing another round of scattered to numerous thunderstorms. Winds aloft are not expected to be terribly strong, but the lift, instability and moisture may again be sufficient to trigger some severe storms with damaging winds. Large hail will be a somewhat bigger threat in the strongest storms than it has been the last two days, and a pool of cold air aloft with the front and an upper-level low-pressure trough may be sufficient to allow ice growth low enough in the atmosphere to survive the fall through hot layers underneath. We may dry out and cool down just a bit (80s highs, 60s lows) for Sunday, but the overall pattern this week will feature additional disturbances/fronts moving southeastward into humid air. It does appear the heat dome will be kept at bay over the central/southwest U.S. this week, so anything approaching triple-digit heat is not expected. August looks to start next week with fairly normal temperatures and daily rounds of hit-and-miss showers and storms, the hitting and missing percentages varying a little from day to day.