"Light pillars" may explain aurora report
The WeatherBlog received an excited report last night from Jeff Ceccola, in suburban Philadelphia:
"Frank,
I believe I [saw] the Northern Lights right here in West Chester, Pa. There was perhaps up to 100 tubes of vertical light ranging from an aqua blue to a magenta all throughout the east through the southern sky. The lights were not moving but I am unsure what else this phenonem could have been. I spoke to all 4 Philly news stations and they said they have had dozens of reports. Any sightings down there? Regards, Jeff."
Before I had a chance to respond, Jeff heard from one of the Philly TV weather guys, and he (Jeff) got back to me with this explanation:
"Per Glenn "Hurricane" Schwartz NBC 10 Philadelphia, he theorized the lights were merely snow flakes reflecting in the moon light. Oh well, pretty nonetheless."
I think Glenn is close. It would be very unusual, this far south, to see the Northern Lights, especially in the eastern and southern skies.
But my guess is that the atmospheric display Jeff saw was most likely what are referred to as "light pillars." They're caused by ground lighting reflecting off flat snow crystals descending through very cold air. Because it's man-made lighting, the light will consist of any number of different colors, which would explain what Jeff saw. In the up-shining beams of light, the descending crystals appear to form colorful columns or tubes.
Here's a link to a site with some amazing photos of a variety of atmospheric light phenomena. Scroll to the bottom for images of artificial light pillars.
Jeff wrote back this morning and agreed:
"Yes, that certainly seems to be the consensus. I fear my unbridled excitement interfered with my logic. Nonetheless, nature once again provided a show that I will not soon forget. It really was beautiful. I have attached a picture that someone sent to the NBC 10, it is a perfect facsimile of what I was seeing last night."
That's the photo at the top of this post. We're always happy to get reports of unusual phenomena in the sky, aurora borealis among them.
Here's a link to a gallery of true aurora borealis images taken in recent days around the Far North. To see these spectacular displays, you need to get yourself beneath the "auroral oval" - the region around the Earth's north magnetic pole where the solar particles raining down on the Earth strike the upper atmosphere and kick off the light shows. (Yellow band in the image below.) 
That oval is currently in far northern Canada. But it does occasionally expand farther south. To check on its current position, click here, and scroll down the lefthand column.
The best chance for seeing the aurorae is during periods of high solar activity. We are currently just emerging from the latest solar "minimum," so we may have to wait a while to have even a slim chance to see them this far south. The last time that happened that I can recall was in November 2004.
