There’s a lot on the radar picture tonight, and at first glance it may appear that some locations are getting a healthy dose of rain.
There are a few lucky folks in northeast Iowa picking up a heavy downpour, but rain is the exception. So what are the rest of the returns on radar?
Windfarms are being picked up on radar in southern Minnesota and northern Iowa. Typically, especially during the day, these windfarms wouldn’t be picked up by NEXRAD Radar, but conditions are just right tonight for atmospheric ducting. Due to an inversion in the atmosphere, something that commonly happens at night after we’ve lost the direct heating of sunlight, the air temperature cools down at the surface but remains warm as you go a couple thousand feet up in the atmosphere. This causes the radiated waves of the radar signal to be “bent” over the surface of the earth instead of radiating directly away from the radar source in a straight line.