From NWS Weather Predictions Center
Summary
Scattered showers and thunderstorms will continue to form and slowly move across the Southern Appalachians tonight. These storms may produce heavy rain, with rates of 2-3 inches per hour, potentially leading to flash flooding in some areas.
Current Conditions
This evening, radar shows thunderstorms developing from northern Georgia, across the Blue Ridge Mountains of North Carolina, and into southwestern Virginia. These storms are forming in very humid air, with moisture levels of 1.8 to 2.0 inches. The storms are also energized by moderate instability, which helps them grow and produce heavy rain.
Weather balloons launched from Atlanta, GA (KFFC), and Roanoke, VA (KRNK), indicate a very moist atmosphere. The data shows that the air is deeply saturated, which supports the efficient production of heavy rain. Additionally, weather patterns are aiding the storms’ development by lifting moist air northward into the mountains.
Forecast
Over the next few hours, scattered thunderstorms are expected to continue developing, especially east of the North Carolina/Tennessee border due to the mountains enhancing the storms. These storms are capable of producing heavy rain, with radar estimating rainfall rates of 2-2.5 inches per hour.
Forecast models suggest a 20-40% chance of rain rates reaching 2 inches per hour, and brief periods of even higher rates are possible. The highest risk for additional heavy rain and potential flash flooding will be in the next 3-4 hours. After that, the wind patterns are expected to shift, which should decrease the intensity and coverage of the storms.
Flood Risk
The region has received a lot of rain recently, with some areas seeing 150-300% of their normal rainfall over the past week. This has saturated the ground, meaning any additional heavy rain could quickly lead to runoff and flash flooding, especially in sensitive areas like valleys and low-lying spots.
Stay alert and be prepared for possible flash flooding. Avoid driving through flooded roads and seek higher ground if you are in an area prone to flooding.