Training Storms Produce Flash Flooding and Localized Tornado Risk in the Southeast

Overview

• A band of training thunderstorms produced observed hourly rainfall rates of 2–4 inches and local totals of 6–10 inches in parts of the southern Appalachians, triggering flash flooding in Murray, Gilmer and Fannin counties Wednesday.
• The Storm Prediction Center tracked small, rotating cells across central and eastern Georgia into Upstate South Carolina that posed a conditional risk for a brief tornado or two and isolated damaging wind gusts while noting watch issuance was unlikely because the threat remained localized.
• Early WPC and SPC guidance on Tuesday flagged training storms ahead of a slow‑moving cold front from northern Louisiana into western Tennessee that could produce 2–3+ inch rainfall swaths and localized flooding.
• The Weather Prediction Center highlighted a conditional urban flash flood risk for southeast Florida where banded convection could yield hourly rates of 2–4 inches and totals up to 3–5 inches in urban areas if cells backbuild toward the coast.
• Forecasters pointed to very high precipitable water, a 20–35 kt low‑level jet, modest MLCAPE and midlevel troughing as the drivers of heavy rain efficiency, and they urged travelers and residents in flood‑prone urban and steep terrain to monitor local NWS office and RFC messages for short‑term flood warnings.