Space Weather
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
There are currently no active notifications.
Aurora forecasts
Northern Hemisphere
There is now a reduced risk of further minor CME influence during the first half of the three-day period, after the passage of a minor transient early on 26 Apr. For aurorae to become visible at high geomagnetic latitudes (e.g. northern Scotland) it is now likely that inbound fast winds and any CMEs would have to be coincident, which is low confidence. The result is that more reliably Quiet geomagnetic conditions should develop later in the period.
Southern Hemisphere
There is now a reduced risk of further minor CME influence during the first half of the three-day period, after the passage of a minor transient early on 26 Apr. For aurorae to become visible at high geomagnetic latitudes (e.g. the extreme south of New Zealand) it is now likely that inbound fast winds and any CMEs would have to be coincident, which is low confidence. The result is that more reliably Quiet geomagnetic conditions should develop later in the period.
Issued at:
Forecast overview
Space Weather Forecast Headline: Declining chance of Moderate-class flares and slight chance of Strong flares.
Analysis of Space Weather Activity over past 24 hours
Solar Activity: Activity is currently Low, with only Common-class flares in the last 24 hours. There are currently nine sunspot regions on the visible disc. The sunspot cluster in the southwest has now rotated beyond the west limb, with a rapidly declining influence on the flare forecast. A region near centre disc has shown significant growth recently, apparently with a new region appearing in the middle of the existing region. An area in the middle of the group is developing some magnetic complexity. Another region in the southwest has shown further development, with a few intermediate spots emerging. A new region has recently rotated around the east limb, although it is difficult to get a detailed analysis at present due to foreshortening. Remaining sunspot regions are all relatively small, simple and stable.
A new Coronal Mass Ejection (CME) has been observed starting around 26/1830 UTC, which emerged from an area in the southeast of the disc. The resulting CME is mostly passing behind and below Earth's orbit, but there is a slight chance of a glancing blow early on Day 4 (30 Apr).
Solar Wind / Geomagnetic Activity: Solar winds have shown the onset of a coronal hole fast wind, perhaps combined with some weak CME influence. Wind speeds started at background levels but rose to become elevated, from around 330 km/s to near 500 km/s. The Interplanetary Magnetic Field has been mostly Moderate, but with some brief Strong peaks between 27/0400-0630 UTC. The north-south component was moderately negative, becoming more variable after 27/0400 UTC. Geomagnetic activity started the period with G1/Minor Storm (Kp 5) intervals between 26/1200-1800 UTC, before declining to be Quiet to Unsettled.
Energetic Particles / Solar Radiation: Solar radiation was at background levels.
Four-Day Space Weather Forecast Summary
Solar Activity: There is a chance of Moderate-class flares and a slight chance of Strong flares, this risk decreasing slightly into Day 2 (28 Apr) as the cluster which was in the southwest rotates well away from the limb.
Solar Wind / Geomagnetic Activity: There is a declining risk of further CME arrivals from the sunspot cluster in the southwest as it has now rotated over the limb. There is, however, a new CME which could give a glancing blow early on Day 4 (30 Apr). There is a series of coronal holes in the western disc, with the initial fast wind now having arrived at Earth. Wind speeds are expected to be at elevated levels of 500-550 km/s through much of Days 1 and 2 (27-28 Apr), before gradually declining thereafter, but with some uncertainty in how fast the wind speeds will decline.
Geomagnetic activity is expected to be Quiet to Unsettled for much of the period, but with a slight chance of Active to G1/Minor Storm intervals, mainly on Day 1 due to a combination of fast wind and potential CME influence, and again on Day 4 due to a possible CME glancing blow.
Energetic Particles / Solar Radiation: Solar radiation is likely to remain at background levels, but with a decreasing slight chance of reaching the S1/Minor Radiation Storm threshold, as the sunspot cluster which was in the southwest rotates well away from the limb.
Issued at:
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.
Issued at: