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Space Weather Alert - 27th February 2023

What Has Happened?

A video showing the CME observed on the 25th February.

Estimated 3-hourly K<sub>GBI</sub> indices (a measure of geomagnetic activity in the UK and Ireland) showing the storm intervals on 27 Feb

Last night (26th Feb) the northern lights were seen across much of the country due to a geomagnetic storm. The storm is continuing and may intensify later today, so further displays of aurora are possible tonight.

Late on 24th Feb there was a coronal mass ejection (CME) associated with an M3.7-class solar flare. The solar wind was already being disturbed by coronal hole effects, when the CME arrived at around 18:30 UT. The combination of CME and coronal hole effects caused a strong geomagnetic storm and spectacular displays of the northern lights.

Around 19:30 UT on 25th February there was another full-halo CME, associated with a long duration M-class solar flare, again from the north-west of the solar disc. This CME is expected to arrive late on 27th or in the early hours of the 28th Feb. Following its arrival there is likely to be an enhancement in geomagnetic activity, with a chance for further strong STORM activity.

Assuming clear dark skies, there is an increased chance of seeing the aurora tonight (27th Feb). Those in Scotland, northern England and Northern Ireland have the best chance if the weather is favourable.


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The British Geological Survey is a geoscience research centre that is part of UK Research and Innovation (UKRI) and affiliated to the Natural Environment Research Council (NERC).

CME or Coronal Mass Ejection
The eruption of a portion of the outer atmosphere of the Sun into space, caused by rapid changes in its magnetic field. Often occurs along with a solar flare.

Coronal Hole
A region in the Sun’s outer atmosphere (corona) where hot material can flow unrestrained by its magnetic fields out into space.

Solar Wind
The ever-present expansion of the Sun’s hot outer atmosphere into the solar system, which carries space weather within it.

Solar Flare
Energy released by the explosive reorganisation of magnetic fields within the Sun's atmosphere.