Heavy rain, strong to severe storms possible overnight

A strong storm system is moving through the Great Plains this afternoon, and it will bring the potential for severe weather to the Southeast this evening.

A cold front associated with this storm system will push a line of heavy rain and thunderstorms through North Georgia tonight, and the line of storms will sweep through Metro Atlanta between 11pm and 4am Wednesday.

The Storm Prediction Center has outlined an “Enhanced Risk” for numerous severe storms this evening in north and west Georgia, including much of Metro Atlanta, which means they will be persistent and widespread, and a few storms will be intense with damaging winds the main impacts from these storms.

The Storm Prediction Center has outlined an “Slight Risk” for scattered severe storms in east Georgia overnight, which means they will be short-lived and/or not widespread, though a few storms will be intense with damaging winds the main impacts from these storms.

Use the Interactive Radar Tracker below to track the storm system throughout the course of today.

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Timing out the squall line

The animation below illustrates the hour-by-hour Futurecast Radar for Tuesday night through Wednesday morning.

Damaging wind gusts are the main impacts from these storms, though a few quick-spin up tornadoes cannot be ruled out.

Wind shear will be quite high in Metro Atlanta after midnight, so while the storms will not have much convective energy available to work with, enough wind shear (change of wind direction and speed with height) will be available to keep the storms strong to severe with damaging wind gusts capable of knocking down trees and powerlines.

The animation below illustrates the convective available potential energy (CAPE) through Wednesday morning. In Metro Atlanta, CAPE values will range between 500 to 1500 J/kg, which is relatively low CAPE.

According to the Storm Prediction Center (SPC), “Storm Relative Helicity (SRH) is a measure of the potential for cyclonic updraft rotation in right-moving supercells, and is calculated for the lowest 1-km and 3-km above ground level.”

The SPC further states, “larger values of 0-3-km SRH (greater than 250 meters squared per second squared) and 0-1-km SRH (greater than 100 meters squared per second squared), however, do suggest an increased threat of tornadoes with supercells. For SRH, larger values are generally better, but there are no clear thresholds between non-tornadic and significant tornadic supercells.”

The animation below illustrates the wind shear (storm relative helicity) available through Wednesday morning. SRH as high as 300 to 500 meters squared per second square are possible in Metro Atlanta between 11pm and 3am Wednesday morning, suggesting that damaging wind gusts and a few brief spin up tornadoes are possible before 4am.