Saturday comes with a risk for severe thunderstorms a potentially prolonged periods of heavy rain.
The severe weather risk for the Tennessee Valley is mainly an elevated risk for damaging wind. Large uncertainties in timing will mean adjustments in the forecast. The timing will play a role in the intensity of the storms, so if the timing shifts enough it's possible that damaging storms may not materialize. However, even if damaging storms do not occur, widespread heavy rain is likely Saturday through Sunday morning. Damaging 60-70 mph wind is the biggest threat from any severe thunderstorms that develop. A brief tornado is possible. Some storms can also contain large hail. Rainfall amounts of 2-4 inches are likely.
The worst case scenario includes damaging storms. Prepare for our potential worst so you're safe. Stay weather aware Saturday and be ready to move to your severe weather safe spot if dangerous weather threatens. The earliest the storms will arrive is 7 AM to 10 AM Saturday morning across the Shoals, 10 AM to 1 PM along I-65 and I-565 around Huntsville, Athens, Decatur, Madison, and Fayetteville, and 12 PM to 3 PM across Sand Mountain. Remember these storms can arrive significantly later. The highest risk for damaging storms happens later in the day -- from about 11 AM through 7 PM.
The rain will last through Sunday morning, coming to an end 5 AM to 8 AM across the Shoals, then at 7 AM to 10 AM around I-65 and I-565, and around 10 AM to 1 PM around Sand Mountain.
Friday will start sunny with 50s in the morning. We will stay dry, but clouds will begin building Friday afternoon. The wind will increase to 15-25 mph. Highs will be in the lower 80s.