UPDATE 9:30 PM: The yellow/orange/red spot on this National Weather Service map southeast of Roanoke represents radar-estimated rainfall totals of 3-plus inches — the red in the middle 5-plus inches. Much of that has occurred in cloudburst downpours since 4 p.m. from the Rocky Mount area east and northeast through Wirtz, Burnt Chimney, toward the west end of Smith Mountain Lake. Rain is resurging in the area again this evening as another upper-level impulse is triggering heavier showers and storms, and upslope southeasterly flow ahead of a low-pressure system continues to bank moisture against the higher terrain of the eastern slopes of the Blue Ridge and the western Piedmont. The Future Cast image I posted last night below appears to have been on the right scent for location of the heaviest rainfall. You can follow the latest location of rainfall on the Radar / Future Cast in the right margin of this blog. END UPDATE
As you can see on the radar display in the right margin, rain is spreading across Southwest Virginia this evening, likely to overtake all of the Roanoke and New River valleys in the next 3 hours. Over the next 36 to 48 hours, there will be several periods of rain, as a slow-moving upper-level low to our west continues to pull it out of the Gulf of Mexico and the Atlantic ocean, hurl it against our higher terrain, and squeeze out heavier periods of it (some possibly accompanied by thunder) as upper-level disturbances traverse the region. I ran the “rain accumulation” feature in the Future Cast at right about 5:30 p.m., and it showed amounts of 1.5 inches widespread over the region through 3 p.m Tuesday with a zone of 2-plus inches generally along the eastern side of the Blue Ridge just east of Roanoke. The National Weather Service in Blacksburg and the Hydrometeorological Prediction Center have similar ideas on rainfall in the region. A soaking period is obviously ahead for Southwest Virginia.