Scattered storms, heavy rain on the way for Sunday

With regards to the rain the past few days, some locations received a lot of rain whereas other areas barely received a drop.

If you’re one of the locations that is begging for rain, your best chance for a good soaking arrives Sunday.

High pressure will push an “atmospheric disturbance” from the Great Lakes south into the Tennessee Valley. This disturbance will serve as a lifting mechanism that will allow widespread showers and storms to form.

Regarding timing the arrival of the storms, it’s difficult to nail down exactly when the storms will form and exactly  where they will go, but the best timeline for storms to develop will be after 12pm through 8pm Sunday.

Here are the nuts and bolts of the thunderstorm forecast:

  • Timing: best chance begins around noon and ends around 9 PM.  Isolated showers may develop before or after that period.
  • Strength: There is not a ‘high’ chance of severe storms, but we do have enough unstable air this weekend for storms to grow very tall.  In this case, the bigger they are, the harder they fall; that ‘fall’ (or collapse) is what causes the strong wind potential.
  • How to plan for it:  Planning for these storms is nearly impossible because there is no way to ‘know’ specifically when and where they will develop.  Our timing forecasts in Spring and Fall severe weather work because we can track a specific feature that will cause storms; these storms are like bubbles in a boiling pot: chaotic.  We can only see the environment they form in; we cannot see the precise locations or strength of storms.  So what do you do? Use the Live Alert 19 app to give you a heads up when lightning is detected within 10 miles of your location.  Be flexible with your outdoor plans, but don’t cancel them as long as you have a way to move indoors if one of these storms approaches!

How much rain should you expect? Based on observations from the previous few days, these storms are capable of producing 1-2 inches of rainfall, depending on how slowly they move over a particular location. Throughout north Alabama and south Tennessee, expect any where from half an inch to two inches of rainfall to occur.

The storms will bring an added benefit to the region as well: cooler daytime highs that remain in the mid to upper 80s. This is contrast to the low to mid 90s that occur when no storms are present. The trade off is that with the higher humidity, the heat index (or “feels like” values) will be much higher until the rain-cooled air arrives.

Will umbrellas be necessary for the week ahead? Check the WHNT News 19 Forecast Discussion.

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