We are looking at a storm threat through the evening and early night hours. This is all from the same complex of storms that initiated in the Dakotas last night and rolled through Chicago this morning. The storms are following a pipeline provided by the jets stream and a ridge pattern. Essentially we are on the eastern fringe of a high pressure ridge, and it's along those fringes where these storm complexes develop and move. The farther east you live, the better your chances of severe storms through 10pm tonight.
As of the 5pm hour, the storms are hitting the high mountains and moving toward McDowell and Rutherford counties. If they can hold together, which that probably will thanks to all the heat and moisture in place, they will hit the eastern Upstate between 7-9pm tonight (rough timing). Damaging wind, hail and lightning will be the main threats. They are fast moving, so flooding shouldn't be an issue, but brief, heavy rain is likely.
So, Spartanburg, Gaffney and Union will have a better chance at storms than Greenville, Clemson and Anderson. BUT, we all need to be on the alert since storms can flare up just about anywhere.
The ridge should build in a bit more for tomorrow and Thursday, which means VERY hot temps and lower storm chances.