Winter mesospheric echoes drift by...

I was glad I checked the MST radar site in mid-Wales today because, if you look on the extreme left hand side, you can see some weak, but coherent polar non-summer mesospheric echoes, or simply winter echoes, were present early morning to mid-afternoon yesterday.

There are no singificant meteor showers at present, and it's a month since the Quadrantids peaked in early January.  So the explanation is interesting to think about.  I don't think anybody really understands these winter echoes, beyond those that arise in association with meteor showers which is, in itself, not a perfect correlation.

One possibility is that a modest-sized bolide entered somewhere over the planet recently, leaving a trail of charged debris behind it.

I'm not able to check data from the MST archive this morning, but a fascinating visual phenomenon that occurred over Wales four days after the Chelyabinsk bolide entry in February 2013 was this stratospheric layer; it's ablated fine dust from the meteorite's passage through the atmosphere.  It travelled eastwards, the 'long way' around, before first being spotted (only once, with no photo) from Alaska, then once in Ireland (with photos) and Wales: