NPP/VIIRS passed over Southern Indiana on March 2 about thirty minutes before the most devastating tornadoes struck the towns of New Pekin and Henryville (among others). At 1935 UTC, a pair of rotating thunderstorms, also known as supercells, were advancing eastward across Indiana. The easternmost storm spawned the most damaging tornadoes. Below is a VIIRS true color image from the NPP pass at 1935 UTC.
A zoomed-in visible view of the storms is below.
The infrared (I-band 5) image is below, along with some annotations pointing out the two active supercells discussed above. Note that the brightness temperatures associated with the overshooting top (OST) of the westernmost storm are colder than the easternmost storm, although both storms were quite strong at the time and the eastern storm ended up producing the deadlier tornadoes. OSTs are transitory, so it’s possible that a new cold OST formed with the eastern storm shortly after the NPP pass. These very high resolution infrared views of tornadic storms are among the first documented, given the recent launch of NPP.
To illustrate the effect of high resolution in the IR, below is a GOES-13 10.7 micrometer IR image from 1932 UTC, which has 4-km resolution at nadir. The coldest brightness temperature in the westernmost storm in southern Indiana from GOES is 206.6 K, but with VIIRS it’s 195 K.
The day after the tornadoes, relatively cloud-free skies in eastern Kentucky allowed VIIRS to see some of the tornado tracks. In the image below, the faint white lines circled in red in Kentucky and West Virginia denote the new tornado damage paths. When green vegetation is disrupted/destroyed, the result is typically a brighter scene at visible wavelengths.