An MCS shifting southeastward across northern IL was producing quite a bit of lightning, and much of it was moving through the southwest portion of the line per Flash Extent Density. From a IDSS standpoint, the Minimum Flash Area and FED proved that it’s necessary to look at both GLM products and ground based lightning products to see the “total” picture. The GLM products captured a larger flash that extended out into the stratiform area behind the main line that is not seen in the ENTLN and NLDN products. This information can be especially important for Airport Weather Warnings and/or outdoor venues. You can easily see that the flash extends almost back to the Rockford Airport, while the main line and most of the flashes are ~80 miles away. In other words, areas near Rockford Airport are not out of the woods yet for lightning.

-Tempest Sooner