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Space Weather Alert Update - 27th April 2023

What Has Happened?

Solar wind data showing the CME passage at the ACE+DSCOVR satellite on the 24<sup>th</sup> April and currently elevated conditions (27<sup>th</sup> April).

Image from the SDO satellite showing the dark regions where the coronal hole is.

 

The recent Coronal Mass Ejection (CME) passage observed on the 23rd and 24th April caused a significant geomagnetic disturbance with activity levels reaching major STORM conditions. Those effects have now subsided.

However, solar wind currently remains elevated due to the influence of the coronal hole high-speed stream (HSS). A possible glancing blow from a CME associated with a filament eruption that left the Sun at 13:00 UT on the 24th April may further enhance the geomagnetic conditions.

Combination of the HSS effects and CME glance will most likely increase the geomagnetic activity over the next 48 hours, with overall ACTIVE conditions and high chances of STORM intervals.

Assuming clear, dark skies, there is a slight chance of seeing the aurora tonight. Those in Scotland, northern England and Northern Ireland have a better chance if the weather is favourable.

 

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Glossary

BGS
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.

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

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

High Speed Stream
A fast moving stream of solar wind, responsible for magnetic storms.

Filament Eruption
An eruption of solar plasma (i.e. ions and electrons) associated with the upward movement of solar magnetic field lines into the corona. Filaments are usually dark against the bright solar disk but can appear bright (as 'erupting prominences') on the limbs of the Sun against the darkness of space. Filaments are often associated with CMEs