Atmospheric River To Soak The Southeast, Including Drought-Stricken Florida

Soggy Southeast: Multiday Flood Threat Ahead

The Southeast, including Florida, will be soaked by an atmospheric river, fueling locally heavy rain the next several days that could trigger flooding, even in drought-stricken areas.

Forecast Timing

A sluggish low pressure system is taking shape in the northern Gulf and across the Southeast.

We’ve already seen several rounds of thunderstorms with hail, strong winds and locally flooding rain the past few days over the South, from Texas to Virginia and the Carolinas.

We expect these thunderstorms with locally heavy rain to persist in the Southeast through the first half of next week.

Florida and other areas near the northern Gulf Coast may begin to dry out by Tuesday.

Gradually, the plume of locally heavy rain will spread north into the Appalachians and mid-Atlantic beginning Monday, and could linger into Tuesday and Wednesday.

(MAPS: 7-Day U.S. Rain Forecast)

Too Much Of A Good Thing?

Through Wednesday, many areas from Alabama into northern and central Florida, Georgia, the Carolinas and Virginia could pick up 2 to 6 inches of rainfall.

Parts of South Florida may see less rain overall, but could still see locally heavy rain where bands of rain or thunderstorms stall.

But this locally heavy rain over multiple days could lead to flash flooding, particularly in urban areas and the hills and mountains of the Appalachians.

(MORE: Peak Time Of Year For Flash Flooding)

Why So Stubbornly Wet?

There are two main reasons for this sluggishly wet forecast.

First, an area of low pressure in the Southeast is being blocked by high pressure to the north. That means it will move very slowly, and slow-moving lows mean slow-moving areas of precipitation.

Second, this Southeast low is tapping a plume of deep moisture known as an atmospheric river.

You may have heard this term used for Pacific storms hammering the West Coast, but they occur around the world, including in the eastern United States.

By Monday or Tuesday, this atmospheric river plume could be almost 2,000 miles long from Central America to the mid-Atlantic states.

Atmospheric rivers can wring out heavy rain due to their incredible moisture content. One study estimated that the moisture flux is roughly equal to that of the Amazon River – about 176,000 tons per second.

Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. Extreme and bizarre weather are his favorite topics. Reach out to him on Bluesky, X (formerly Twitter) and Facebook.