Noctilucent Tornado

27 Jun 2018

At (June 25th 2018) there is a nice image of noctilucent clouds over Meghara in Co Derry. It was taken by Martin McKenna who said, their brightness and complexity has been getting more enhanced since the solstice, with whirls and knots glowing electric blue above a yellow midnight sun horizon. The tornado was once such formation - morphing into a succession of dynamic shapes (a wdge, a funnel, angel wings, an electrified smoke ring, and finally a long rope that resembled a tornado, reaching towards the far side of the sky. These  shapes are said to be created by gravity waves - waves of pressure and temperature in a storm system. Gravity does not vary inside the wave. It acts as a restoring force that tries to keep equilibrium to the up and down movement of the air. This process is seen near the surface of the earth - and in all of the atmosphere (even at the very top where noctilucent clouds form).


Another odd phenomenon is the twin rainbow. The image below was taken by Jan Curtis over Cheyenne in Wyoming. It followed on the tail of an extensively severe thunder storm. We are told that the actual cause of twinned rainbows is a subject of controversy - with differing opinions. They might form from water droplets and ice spheres, or from non-spherical raindrops (flattened as they fall through the air).

   and today, June 27th, there is a 70% chance of a geomagnetic storm as a stream of solar wind hits earth's magnetic field. It is flowing from an irregular hole on the Sun - so aurorae in northern latitudes are to be expected.