Aurora over the northern United States
The Space Weather Prediction Center (link) has recently noted strong solar activity as part of the ongoing solar maximum (see the images below from 10 May and 11 May). The result on 11 May was an aurora borealis observed south into the United States. The Day Night Band image above, from Suomi-NPP, shows the light of the Aurora stretched out like a necklace across the northern United States. (Additional views of Day Night imagery are available at VIIRS Today showing NOAA-20 and Suomi NPP and at the VIIRS Imagery Viewer that also includes NOAA-21 Day Night Band imagery). Imagery is also available at the CIMSS Direct Broadcast site.
Day Night Band imagery along the east and west coasts (below) show how the character of the auroral display changed during the night.
A strong Aurora australis also occurred on 11 May (link).