Okay, last night was a weird one. If you just look at the base reflectivity, you won’t see much. Check out the velocity though, winds last night were light and variable, but if anything, had a slight northerly component. The velocity shows something entering the radar from the south after sunset, and then moving north throughout the night. This is the typical nocturnal migration signature. So why nothing on the base reflectivity? It could be that the birds that were migrating were doing so at low altitude, such that they were mistaken for “ground noise” by the radar filters, and therefore filtered out of the images before being posted to the web. I checked the real-time radar site and indeed there was some low altitude signal present. It seems impossible that this could have been due to something else on the ground- since nothing else (dust, pollen, insects, etc.) has the ability to move against the wind at speeds of 10 – 20 kts. The definite movement of birds out of N. Carolina and Virginia supports this analysis as well. After checking the bird reports from those areas, I wouldn’t expect much new diversity, although we could begin to see things like Blue-gray Gnatcatcher showing up on this little push. This wasn’t a big movement, but it should produce some diversity and density changes across the southern half of the state.