Rain broke up on approach to the Tennessee Valley Thursday afternoon. New development over Mississippi will track through the Valley Thursday evening. Some spots may stay dry, but showers and heavy thunderstorms will be around. The chance for rain is biggest early. It will lower from 6 PM to 9 PM, then drop off through midnight before increasing again between midnight and sunrise Friday. That could mean a rainy, slippery morning drive with areas of reduced visibility.
For Friday, one or two stronger storms can form. While the overall risk level for a severe thunderstorm is minimal, remember just one severe thunderstorm can make the day a bad one those it impacts. Any stronger storms, though isolated, will be capable of producing winds of 50-60 mph. The biggest threats on Friday will be heavy rain and frequent, dangerous lightning. Rainfall amounts through midnight Friday will average between a half-inch and inch.
Rain may be scarce Thursday night. It can begin increasing by the morning drive Friday. The biggest batch of rain will arrive in the Shoals between 10 AM and noon Friday. It will track eastward, crossing I-65 and moving into Huntsville and Madison between noon and 2 PM, then moving into Sand Mountain between 2 PM and 4 PM. Some variation in timing is possible. The bottom line is this: be ready for rain, which can fall heavily at times.
Periods of rain will likely last through Tuesday. Rainfall amounts through Tuesday will average between three inches and four inches. Cooler and drier air will follow the rain's exit on Wednesday and Thursday.