Tornadoes:

Tornado - SW Effingham County EFFINGHAM COUNTY Date April 3, 2018 Time (Local) 4:34 - 4:41 pm CDT EF Rating EF-1 Est. Peak Winds 110 mph Path Length 7.4 miles Max Width 100 yards Injuries/Deaths 0 / 0 Summary: The tornado destroyed 5 outbuildings, a large grain bin, and a garage about one-half mile east-northeast of where it entered southwest Effingham County. The tornado also damaged the windows of a home and an automobile. As the tornado tracked to the east-northeast around 60 mph it damaged three additional farmsteads, where it damaged or destroyed six additional outbuildings, a camper, an unoccupied trailer, and numerous trees. The tornado dissipated in a forested area about 3.4 miles NW of Mason, IL. Track Map Downloadable KMZ File

EF1 Tornado Damage to outbuilding EF1 Tornado Damage to outbuilding EF1 Tornado Damage to barn EF1 Tornado Damage to outbuilding

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Radar:

Evansville, IN Radar Images

Figure 1 -- 4:20 pm	Figure 2 -- 4:27 pm	Figure 3 -- 4:33 pm	Figure 4 -- 4:42 pm

These images were taken from the Doppler radar located north of Evansville, IN. While our radar was operational during the time, this part of Illinois is closer to the Evansville radar, thus the radar beam is looking lower in the storm.

Each image has 4 sub images within it. These were all from the lowest elevation angle (0.5 degrees above the horizontal plane):

• Top left:  Reflectivity -- This is the standard radar image you're used to seeing. It shows areas of precipitation.
• Top right:  Storm Relative Motion -- This shows the wind motion within the storm, factoring in the movement of the storm itself. Red areas are moving away from the radar (located off the lower right corner), and green is moving toward the radar. 
• Lower left:  Differential Reflectivity -- Dual-polarization radars have a horizontal and vertical component of the radar beam. This product shows the difference between the two. It can help us determine areas that may be seeing snow or hail vs. rain. 
• Lower right:  Correlation Coefficient -- This product shows us how similar the two radar beam components behave. This helps us distinguish meteorological echoes, such as rain, from non-meteorological echoes, such as birds, insects, and tornadic debris in the air. 

A circulation began to develop while the storm was over southeast Fayette County. In Figure 1, the red and green echoes are right next to each other in the top right quadrant of the picture, highlighted by the yellow circle. In Figure 2, the lower right quadrant is showing a green/blue area lining up with the circulation; this indicates debris being kicked up in the air. (Survey results from the St. Louis NWS indicate that an EF-2 tornado was occurring in this area.) This debris signature persists as the storm crosses the Effingham County border (Figure 3), finally starting to fade shortly after 4:40 pm (Figure 4).

Storm Reports

This tornado was part of a larger severe weather outbreak, which extended from eastern Texas to the upper Ohio Valley. In the map below, courtesy of the Storm Prediction Center, tornado watches issued on April 3rd are highlighted in red, with severe thunderstorm watches in purple. The actual severe weather reports are represented by the symbols on the map.