More Heavy Rain and Severe Thunderstorms Are Ahead for Southeast, But How Much More Rain Is Needed to End the Drought?

Linda Lam
Published: December 2,2016
After going 1 to 2 months without any rainfall, parts of the South will now see yet another round of soaking rain into early next week.
Many areas still need a substantial amount of rainfall for drought conditions to be removed. However, this rain is helpful in bringing some drought relief, as well as in assisting the fight against the wildfires.
(MORE: Latest on Gatlinburg, Pigeon Forge Wildfire)
Amazingly, however, this rain could be "too much of a good thing", triggering flash flooding in some areas.

The Forecast

An upper-level low swirling over northwest Mexico will very slowly eject over the southern U.S. early next week. Ahead of that feature, an east-west oriented frontal boundary will lift a fetch of deep Gulf moisture, wringing out a broad area of soaking rain.

Rainy setup for this weekend.

Here is the current expected timing of the rain:

• Saturday: Moderate to locally heavy rainfall will stretch from Texas into the Lower Mississippi Valley. Overnight the rain will spread into the Tennessee Valley and possibly as far east as the western Carolinas by early Sunday morning. The northern extent of the rain may reach into Missouri and southern Indiana.
• Sunday: Wet conditions are expected from central Texas through the Carolinas and northward into the Ohio Valley.
• Monday: Rain will persist to start of the work week across the South.
• Tuesday: Showers may linger in the Southeast, as an area of low pressure moves out of the region. 

Abundant moisture will accompany this system, bringing locally heavy rain at times.
(MAPS: Weekly Planner)
Rainfall will likely be in the 1 to 3 inch range for much of the South, while areas from eastern Texas and southern Arkansas into Louisiana, Mississippi and into portions of Alabama and Georgia may see total greater than 3 inches. The heaviest rain appears to be in Southeast Texas and western Louisiana.
Flash flooding may develop in some areas as well, especially if and where repeated rounds of heavy rain develop.
(FORECAST: Atlanta | Nashville | Birmingham | Jackson, Mississippi)

Rainfall Forecast

Thunderstorms are also expected, especially in southern Texas, Louisiana and into Mississippi, Alabama, southern Georgia and into the panhandle of Florida. There is the chance of a few severe thunderstorms developing, but it is too early for details.
However, it currently appears the highest chance for severe thunderstorms will be on Monday from Louisiana into southern Alabama and Mississippi.

Monday's Thunderstorm Forecast

The rain will also keep temperatures cool for much of the region, with most areas seeing highs near to slightly below average. This translates into temperatures topping out in the 40s and 50s, with 60s toward the Gulf Coast.
(MORE: December Temperature Outlook)
This wet pattern will likely continue across the South through next week, which is good news.
Check back to weather.com for the latest forecast updates.

How Much More Rain Is Needed

The amount of rain that has fallen so far varies across the region.
This week, through Wednesday, the following rainfall totals have been reported:

• Jackson, Mississippi: 2.82 inches
• Birmingham, Alabama: 2.06 inches
• Huntsville, Alabama: 4.55 inches
• Nashville, Tennessee: 1.72 inches
• Chattanooga, Tennessee: 5.42 inches
• Knoxville, Tennessee: 5.51 inches
• Atlanta, Georgia: 2.98 inches
• Macon, Georgia: 1.15 inches
• Asheville, North Carolina: 1.54 inches
• Greenville, South Carolina: 1.88 inches

This soaking rain has been beneficial and in some spots, including Knoxville and Chattanooga, which have now received more than their normal November rainfall in just the last few days.
(MORE: Thirsty Southern Drought Areas Finally Have Seen a Widespread Soaking)
However, significant precipitation deficits persist across the region. Through Nov. 30, Atlanta and Asheville, North Carolina, remain more than 10 inches below average since the beginning of the year and Birmingham, Alabama, is more than 11 inches below average year-to-date.

Precipitation needed in 4 weeks to end drought conditions.
(NOAA)

The above graphic shows how much more rain is needed to end the drought in the Southeast.
The areas in blue and purple indicate where more than a foot of rain is necessary over a four week time period to end the drought, including portions of eastern Tennessee, southwestern North Carolina, northwestern South Carolina, northern Georgia, northern Alabama and east-central Mississippi. Locations in central Georgia, central Alabama and parts of Mississippi highlighted in red are where 9 to 12 inches of rain is necessary to end drought conditions.
(PHOTOS: Deep South Drought, November 2016)
These values are estimates and do not take into account whether it is a heavy down pour or steady rain. This data is also as of Nov. 26, 2016, so it does not take into account the rain that fell this week.
MORE: Gatlinburg, Tennessee Wildfire, November 2016 (PHOTOS)