Flooding Concerns Increase Monday Across Middle Tennessee

Rain has already been fairly widespread across Middle TN, mainly south of us and additional rounds of showers and thunderstorms are expected on Monday. As a result, the potential for localized flooding continues to increase, especially in areas that see repeated heavy downpours.

There are still some uncertainties regarding exactly where the heaviest rainfall will occur, but the overall setup supports the possibility of flooding concerns developing in parts of the region.

Here's a closer look at what we're watching and why Monday bears close attention.

Why The Flood Threat Is Increasing

A very tropical air mass will remain in place through Monday. Dew points are expected to stay in the 70s, while Precipitable Water (PWAT) values climb above 2 inches.

The atmosphere is basically going to be a giant wet sponge.

Or, if you prefer a Tennessee summer analogy, imagine the air wearing a soaked hoodie in July.

The bottom line is that the atmosphere will be loaded with moisture, which means any shower or thunderstorm that develops will have the ability to dump torrential rainfall in a short amount of time.

This is not a setup where everyone receives heavy rain all day long. In fact, many locations may simply experience a few passing showers and thunderstorms.

The concern is that a few communities could see repeated rounds of heavy rain while areas just a few miles away receive much less.

Flooding Is Not Guaranteed Everywhere

One of the most important things to understand is that flooding impacts will likely be highly localized.

Some locations may receive less than an inch of rain.

Others could receive several inches.

The difference will come down to where thunderstorms repeatedly develop and move. The greatest concern involves slow-moving thunderstorms and a process known as training.

Training occurs when multiple storms repeatedly move over the same location, much like train cars moving down the same track.

When that happens, rainfall totals can quickly add up and overwhelm drainage systems, creeks, streams, and low-lying areas.

How Much Rain Could Fall?

Most locations across Sumner County will likely receive between one-half inch and two inches of additional rainfall through Monday.

However, forecast guidance continues to suggest that a narrow corridor could receive significantly more.

Several models, including the latest HRRR runs, indicate the potential for localized rainfall totals of 4 to 6 inches where storms repeatedly track over the same area.

And remember...

This would be on top of rainfall many locations have already received some, which most of Sumner didn't.

These tropical-style heavy rain setups are notoriously difficult to forecast with precision.

The corridor could shift 25 to 50 miles north or south depending on where storms repeatedly form.

That means everyone across Middle Tennessee should pay attention to forecasts and be prepared for changing conditions.

Flood Watch In Effect

Grab your floaties because we’ve got a Flood Watch in effect until Monday evening.

The Weather Prediction Center has put a big ol’ “Slight Risk” (that’s Level 2 out of 4, if you’re keeping score) for Excessive Rainfall over a large chunk of Middle Tennessee.

This alert is a bit like what the Storm Prediction Center does when they talk about severe weather, but instead of worrying about thunderstorms throwing a tantrum, we’re focusing on the risk of flash flooding. Yes, those sneaky puddles can turn into mini rivers before you know it!

Being at Level 2 means that scattered flash flooding could be on the menu. Some areas might get hit harder than others, especially if the rain decides to camp out and keep pouring in the same spot. So, keep an eye on the sky and maybe have a backup plan for your picnic!

Heavy Rain Is The Main Concern

While a few thunderstorms could produce gusty winds, flooding remains the primary concern.

Ground conditions are becoming increasingly saturated across portions of the region.

As soils become saturated, additional rainfall is less likely to soak into the ground and more likely to run off into creeks, streams, and low-lying areas.

This increases the risk of:

• Flooded roadways

• Water covering low water crossings

• Rapid rises on small streams and creeks

• Ponding of water in urban areas

• Localized flash flooding

A few stronger storms could also produce gusty winds capable of bringing down tree limbs or isolated trees, especially where soils have become saturated.

Timing

The greatest concern for flooding extends from sunrise through sunset Monday.

That may sound like a large window, but that's because this will not be a continuous rain event.

Instead, showers and thunderstorms will develop at different times throughout the day.

Some communities may experience only a brief downpour.

Others may see multiple rounds of heavy rain.

The exact placement of those heavier bands remains uncertain.

Looking Beyond Monday

Rain and thunderstorm chances will continue through much of the upcoming week.

The good news is that widespread organized severe weather is not expected.

The bad news is that the atmosphere will remain very moist, meaning any storm that develops will continue to be capable of producing heavy rainfall.

By the second half of the week, rain chances become more scattered, but temperatures and humidity begin climbing.

Highs are expected to return to the upper 80s and lower 90s, with heat index values approaching or even exceeding 100 degrees in some locations.

In other words...

From Flooding concerns to Heat and Humidity concerns

Remember,

Not everyone will experience flooding on Monday.

But the communities that end up underneath repeated thunderstorms could see significant rainfall totals and localized flooding issues develop quickly.

If you encounter a flooded roadway, turn around and find another route.

Never drive through floodwaters.

As always, I'll be monitoring radar trends, rainfall reports, and forecast updates throughout the day Monday. If you don't follow SumnerSevereWx on FB, X, YouTube and BlueSky, please go follow. I update regularly on those accounts.

If you receive heavy rainfall or experience flooding in your area, please send reports safely if you're able. You can report on the Report page on the Website or Via social media.

Stay weather aware, and I'll keep you updated as conditions evolve.