Space Weather
Space weather describes changing environmental conditions in near-Earth space. Magnetic fields, radiation, particles and matter, which have been ejected from the Sun, can interact with the Earth’s upper atmosphere and surrounding magnetic field to produce a variety of effects.
Space weather notifications
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Aurora forecasts
Northern Hemisphere
No significant enhancements to the auroral oval are expected before 22 July (UTC), when the arrival of a coronal hole high-speed stream is likely. Minor enhancements are then possible, with a chance of aurora becoming visible from northern Scotland and other locations at similar geomagnetic latitudes. However, the short hours of darkness at this time of year will significantly limit viewing opportunities.
Southern Hemisphere
No significant enhancements to the auroral oval are expected before 22 July (UTC), when a coronal hole fast wind is expected to arrive. Minor enhancements are then possible, with a chance of aurora becoming visible from the far south of New Zealand and similar magnetic latitudes.
Issued at: 20:36 (GMT) on Mon 20 Jul 2026
Forecast overview
Space Weather Forecast Headline: Further Moderate-class flares likely. Increasing chance of G1/Minor Storms Days 2-3 (22-23 Jul).
Analysis of Space Weather Activity over past 24 hours
Solar Activity: Solar activity has been Moderate, with three Moderate-class flares observed, all from the region near the centre disc.
There are five sunspot regions on the visible disc. One region has grown significantly over the past 12 hours, developing a complex magnetic structure with north–south-oriented opposite-polarity spot arcs as well as a weak delta configuration. The other regions are magnetically simple and stable
A filament eruption was observed at approximately 20/0500 UTC near an active region in the southwest quadrant. However, the erupted material appears to have been largely reabsorbed, and the event is not expected to have produced a CME (Coronal Mass Ejection). No Earth-directed CMEs are currently present in the forecast.
Solar Wind / Geomagnetic Activity: Solar winds have been indicative of a slow regime. Solar wind speeds have remained below 300 km/s. Total Interplanetary Magnetic Field was weak, with the north-south component also varying weakly. Geomagnetic activity was Quiet (Kp 0-1).
Energetic Particles / Solar Radiation: The count rate of energetic particles (high energy protons) was at Background levels.
Four-Day Space Weather Forecast Summary
Solar Activity: Low to Moderate activity is likely to continue, with further Moderate-class flares likely, mainly from the region near the centre disc.
Solar Wind / Geomagnetic Activity: No Earth-directed CMEs are currently expected during the forecast period. Solar winds are slow. The main feature of interest is a large, recurrent coronal hole which may give wind speeds around 450 km/s on Day 2 (22 Jul), increasing to 700 km/s on Day 3 (23 Jul), although with some uncertainty in timing. Winds speeds perhaps gradually easing on Day 4 (24 Jul).
Geomagnetic activity is forecast to be mainly Quiet to Unsettled Day 1 (21 Jul), with an increasing chance of Active to G1/Minor Storm intervals during Days 2-3 (22-23 Jul) as the anticipated coronal hole fast wind arrives, before activity gradually wanes on Day 4 (24 Jul).
Energetic Particles / Solar Radiation: The count rate of energetic particles (high energy protons) is expected to remain at background levels.
Issued at: 00:10 (GMT) on Tue 21 Jul 2026
Solar imagery
SDO AIA-193
This channel highlights the outer atmosphere of the Sun - called the corona - as well as hot flare plasma. Hot active regions, solar flares, and coronal mass ejections will appear bright here. The dark areas - called coronal holes - are places where very little radiation is emitted, yet are the main source of solar wind particles.
Issued at:
SDO AIA-304
This channel is especially good at showing areas where cooler dense plumes of plasma (filaments and prominences) are located above the visible surface of the Sun. Many of these features either can't be seen or appear as dark lines in the other channels. The bright areas show places where the plasma has a high density.
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