A moist, tropical air mass looming over the southeast in early April of 2022 set the stage for a two course dinner of severe weather with a swath of tornadoes throughout.
Figure 1: Image of mobile home completely destroyed by EF3 intensity tornado in Allendale County, SC April 6th, 1 day after the tornado passed through
Central Georgia bore the brunt of the severe weather onslaught on April 5th, as a large mesoscale thunderstorm system swept through the region. Alongside intense straight line winds and intense precipitation, the system spawned a total of fifteen tornadoes during the afternoon and evening hours. While the majority of these tornadoes registered as EF-0 to EF-1 in intensity, several exceptions caused emergencies along the South Carolina-Georgia border and time and time again, high tech radar technology and satellite imagery proved invaluable to emergency responders and meteorologists.
Figure 2/Figure 3: GEOS-16 Airmass RGB 4z April 4 (left) / GEOS-16 Convection RBG 18z April 5 (right)
RGB Satellite products provide perfect examples of the practical impact satellite imagery provides to meteorologists. RGB satellite products assign an individual wavelength of light to each spectral channel, yielding a new image painting a whole new meteorological picture. On the days leading up to April 5th, forecasters monitored upper level atmospheric conditions through the lens of RGB products. Figure 2 displays Airmass RGB, which classifies large masses of air. Moist, tropical air shows up as green. Tropical air provides fuel to thunderstorms, and the figure shows those conditions above the southeast the day before the event.
Even after storms ramp up, RGB products can allow meteorologists to track their progression and intensity. Figure 3 displays Convection RGB, which highlights deep convective clouds with yellow and red. Convection is the engine which powers thunderstorms, bringing a constant supply of moisture to the heart of the system. As you can see, the storm above the southeast is full of convective flow.
Figure 4: Radar 0.3 degree base reflectivity, 20:58z April 5
Figure 5: Dual-pol Radar 0.3 degree correlation coefficient, 20:58z April 5
As the chaos of severe weather ensues, having the ability to immediately identify active tornadoes as they occur is life-saving. Dual-pol radar gives us the ability to do this. Only widespread in 2011, dual-polarization, or dual-pol radar allows us to collect information about the shapes of particles in the atmosphere. An important result of this is the ability to identify debris balls of active tornadoes. When a dual-pol radar detects a debris ball, meteorologists can know that a tornado has touched down, and emergency notices need to immediately be made. Figure 4 and 5 show two types of radar images, reflectivity and correlation coefficient. The former shows the concentration of particles in the atmosphere, and the latter shows how inconsistent the shapes of the particles are. As you can see, low correlation coefficient (colored in blue), can identify the debris ball of an active tornado. And in fact, figures 4 and 5 are of the Allendale county tornado on April 5th.
Figure 6: Surface analysis 18z April 6
The atmospheric instability persisted into April 6th, ushering in another wave of severe weather across the affected states. As the cold front moved in from the northwest (figure 6), the remaining moisture in the atmosphere materialized as a second wave of thunderstorms. Central Georgia once again found itself in the crosshairs of severe weather, with reports of large hail and damaging wind gusts filtering in throughout the afternoon and evening. An additional six tornadoes, ranging from EF-0 to EF-1 in strength, added to the tumultuous weather narrative of the region. The severe weather threat finally subsided with the passing of the cold front the night of April 6th. This event highlights the pivotal role of satellite imagery and radar technology in monitoring and forecasting tornado activity, enabling timely warnings and potentially lifesaving interventions in the face of nature’s fury.