Following on from yesterday’s post. As there has apparently been a coronal mass ejection in our direction as well as the fast stream of the solar wind hitting us from a coronal hole, keep an eye looking towards the polar region for a higher than normal chance of seeing an aurora, though this chance is slowly receding.
There are monitoring systems out there to give warnings. This website shows the real time extent and activity level of the auroral oval. This one is a more advanced version of the same, but with older readings. This one registers the radio signal caused by radio waves bouncing off the region of enhanced ionisation. Spaceweather.com gives an overall status every now and again and the Kp index (a scale of geomagnetic disturbance with some correlation to the aurora) is the basis of the twitter and email based aurora alerts. But what does Kp index translate into? The contours on this image show where a given Kp influenced aurora should penetrate to (click on the edges of the map to be taken to Australia/America etc for auroral contours at other locations). If you’re on the next contour down (ie the Kp index is within 2 digits of reaching you) the aurora should be visible (faintly) a fist’s length or so above the horizon.
So, from here a Kp of around 7.5 should give an aurora right overhead. Yesterday’s peak was around 7, which would’ve given definite aurora to the north. If it hadn’t’ve been daylight. And cloudy.
Still cloudy now…