UPDATE 4 PM: The part of the tornado watch that affected counties just east and north of Roanoke has been cancelled. We await the storms overnight from the west and southwest. END UPDATE
UPDATE 1:45 PM: The central part of Virginia westward to Alleghany, Rockbridge, Botetourt, Bedford, Franklin and Henry counties (Roanoke/Roanoke County/Salem just barely notched out of it) are under a tornado watch until 8 p.m. This is for the showers/storms currently developing along the Blue Ridge that will encounter strong enough instability and wind shear to intensify through the afternoon as they move northeastward. Quoting the Storm Prediction Center in the discussion linked to the watch: “THE TORNADO THREAT IS NOT PARTICULARLY HIGH…BUT SUFFICIENT LOW LEVEL SHEAR IS PRESENT FOR A RISK OF ISOLATED SPIN UPS IN THE MOST INTENSE SUPERCELLS.” So nothing on the order of the April 16 outbreak is anticipated, but localized tornadic spinups are possible. END UPDATE
As of Tuesday night, the “moderate risk” area for severe weather on Wednesday brushes the far southwest tip of Virginia near Wise — but it covers a wide swath of territory to our west including most of Ohio, Kentucky, and Tennessee. (Click here to see the current Storm Prediction Center outlooks, due to be updated early Wednesday morning.) What is expected to transpire Wednesday is that a large number of storms and storm clusters — some left over from Tuesday’s outbreak, some newly formed during the day — will produce widespread severe weather in the moderate risk zone, including large hail, high winds and scattered tornadoes. By Wednesday evening, these storms will link into a squall line and blow through here Wednesday night with a quick jolt of gusty winds, heavy downpours, and some booming thunder. Winds at the surface are not expected to become as angled to southeast or as strong as they were when tornadoes raked the Carolinas on April 16 — more south to south-southeast — so we probably won’t have the same level of directional shear in the atmosphere we did then. There is enough shear, though, along with strong lift with the advancing front, and definitely warmth and moisture, that we need to keep a close watch on this during the day Wednesday. There may also be some more discrete storms develop ahead of the squall that will have a chance to be acted on even more by the swirling winds aloft. High winds are the major threat with Wednesday’s storms, but large hail is possible, and there probably will be at least a few tornado reports within a couple hundred miles of Roanoke on Wednesday, with a slight chance of some in a 50-mile radius. The front will push through late Wednesday night and early Thursday and return us to more typically springlike temperatures by Thursday and Friday.