
Sun activity for July 20, 2023. Big northwest blast, AR3363 M flaring from afterlife
Today’s top news: An enormous explosion on the northwest quadrant in the vicinity of AR3372 occurred at around 22:37 UTC on July 19. The blast was associated with a C3.0 flare from a long filament explosion by an unnumbered region located between AR3372 and the northwest limb (edge). The flare was accompanied by a gorgeous dancing prominence and a coronal mass ejection (CME) that we saw being hurled into space. Initially, specialists found the bulk of the ejecta too far north to be Earth-directed. Modeling and analysis, however, will continue as soon as coronagraph imagery is available. Almost simultaneously with the eye-catching blast, a filament on the southwest sent a jet of plasma hurtling into space. It was fairly large, but compared with the huge explosion and prominence, it looks quite small! In the meantime, our departed hero AR3363 is still throwing out M flares. It has already rotated beyond the solar southwest horizon, but is continuing to produce registered M flares. Even larger flares could very well be occurring beyond our field of view!
Last 24 hours: Sun activity remains moderate. Between 11 UTC yesterday and 11 UTC today, we observed 14 flares. Two of these were M flares, and the rest were C flares. Both Ms were blasted by sunspot region AR3363 from beyond the solar horizon on the southwest. The first was an M1.4 at 11:07 UTC, July 19, and the second – the largest of the period – was an M3.8 flare that exploded at 17:25 UTC, July 19. Shortly after each M flare, an R1 (minor) radio blackout was registered over Earth’s sunlit northern hemisphere. The lead flare producer is still AR3363, despite having rotated beyond the southwest solar horizon. The sun today bears eight labeled active regions on its Earth-viewed side. Two are newcomers: AR3378 on the southeast quadrant, and AR3379 on the northeast limb (edge).
Next 24 hours: The forecast is a 99% chance for C flares, a 50% chance for M flares, and a 15% chance for X flares.
Next expected CME: The big filament explosion mentioned above hurled a coronal mass ejection (CME) into space. Initially, the beautiful ejecta was observed to have a trajectory too northerly to affect Earth. Nevertheless, modeling and analysis will be conducted as soon as imagery is available. No other Earth-directed CMEs were observed using the available imagery.
Current geomagnetic activity: Earth’s magnetic field is quiet at the time of this writing (11 UTC on July 20). An increase in geomagnetic activity is anticipated later on today. There are chances it could reach a G1 (minor) to G2 (moderate) geomagnetic storm level. This is in response to the arrival of a coronal mass ejection from the M5.7 flare by AR3363 on July 17, combined with any potential bulk plasma influence. These conditions are likely to be extended into July 21. Aurora-chasers, get ready!


Sun activity for July 19, 2023, is going strong! 3 Ms and a CME on its way
For the second day in a row, we’ve seen one, two, three M flares in quick succession. This time the back-to-back M flares came from AR3363 and AR3376. The three Ms exploded in the span of less than an hour, with the largest being an M2.1 flare from AR3363 at 20:27 UTC on July 18. Now at the very edge of the southwest limb, giant sunspot AR3363 continues flaring and is, once again, the lead flare producer of the day. What a spot! Today’s other M flare producer, AR3376, is showing an interesting north-south magnetic configuration and an anti-Hale alignment, meaning that its magnetic field is reversed compared to other sunspots in the same solar hemisphere. This may be a factor in its production of M flares, and could be a source for more blasts as AR3376 transits the Earth-viewed side of our sun. We’ll watch closely. By the way, yesterday’s M5.7 flare from AR3363 continues to be the source of discussion. The highly energetic long-duration flare created a polar cap absorption S1 particle event, and a coronal mass ejection (CME) with a partial halo. Despite having occurred far to the southwest, a component of this CME is anticipated to reach us at Earth with a glancing blow on July 20, which may bring G1 (minor) to G2 (moderate) geomagnetic storms and auroral displays. Aurora-chasers, get ready!
Last 24 hours: Solar activity is now considered moderate. Between 11 UTC yesterday and 11 UTC today we observed 17 flares: three Ms and 14 Cs. The first two M flares were produced by AR3376 – an M1.3 at 19:48 UTC and an M1.4 at 20:05 UTC – and the third and largest was an M2.1 flare from AR3363 at 20:27 UTC (all on July 18). After each M blast, an R1 (minor) radio blackout affected an area over the west coast of Mexico by Baja California. The leading flare producer of the period was sunspot AR3363, sitting at the very edge of southwest limb in a foreshortened position that makes it difficult to analyze fully. It produced eight flares, the M included. The sun today bears seven labeled active regions on its Earth-viewed side.



Sun activity for July 18, 2023, is high! At Earth, a geomagnetic storm
AR3363 kicked things into gear at the end of July 17, with three back-to-back M flares. We observed an M2.7, an M5, and finally a long-duration M5.7, strong enough to bring activity levels to high. This long-awaited action from AR3363 comes as it has nearly rotated out of view. The M5.7 produced a spectacular eruption, firing out a coronal mass ejection (CME). The CME is not heading directly for Earth, but NASA’s modeling forecasts a glancing blow on July 20. The location of the eruption is very conducive to a particle event. This is due to the way that the sun’s magnetic field spirals away toward us, like a particle highway providing a direct route from the sun to Earth. An S1 particle storm was measured at the GOES spacecraft. Meanwhile at Earth, the anticipated G1 (minor) geomagnetic storm was observed late on July 17 to early July 18.
Last 24 hours: The production of three back-to-back M flares, one of them surpassing the M5 threshold, has raised the sun activity level to high. Between 11 UTC yesterday and 11 UTC today we observed 17 flares: four Ms and 13 Cs. The largest was an M5.7 flare by sunspot AR3363, blasted at 0:06 UTC on July 18. Here’s the breakdown of the M flares, with all times in UTC:
M2.7 from AR3363 at 22:54 on July 17,
M5.0 from AR3363 at 23:34 on July 17,
M5.7 from AR3363 at 0:06 on July 18, the largest,
M1.5 flare from an unnumbered active region on the northeast limb (edge) at 6:56 on July 18.
Each M flare caused a corresponding radio blackout:
R1 (minor) at 22:57, affecting an area over Hawaii,
R2 (moderate) at 23:34 affecting an area over the Pacific Ocean,
R2 (moderate) at 0:06 affecting an area over the Pacific Ocean,
R1 (minor) at 6:56 affecting an area over India.
The sun currently has eight labeled active regions on its Earth-facing side. Three are newcomers: AR3375, AR3376, and AR3377.




Sun activity for July 17, 2023: CME or CMEs arrive, sun action continues
The shock wave from a coronal mass ejection CME arrived at Earth at 19:20 UT on July 16. The arrival was earlier than anticipated. But it is not clear if the CME (or CMEs) was (were) just faster, or if it was from a different CME than anticipated. There were several events and the available imagery was limited, making a definitive determination difficult. So this could have been due to the predicted cannibal CME (see yesterday’s entry, below) or one of the other events over the past few days. The arrival disturbed the geomagnetic field enough to cause a G1 (minor) geomagnetic storm at 23:59 UT on July 16. The storm lasted for a few hours, but was otherwise unremarkable. AR3363 has almost rotated out of view but not without giving us an M4 flare.
Last 24 hours: Sun activity is moderate with two M flares. The largest event was an M4.0 from AR3363 at 17:36 UT. This caused an R1 radio blackout over the sun-facing side of Earth. The sun also produced 20 C flares between 11 UTC yesterday and 11 UTC today. AR3372 has not lived up to its beta-gamma-delta magnetic complexity while the simpler AR3373 produced the most of the C flares. There has been a lot of continued jet and ejecta action from AR3363 along with a few scattered small filament eruptions on the disk. An unnumbered region on the southeast limb (edge) looks promising so we wait to see what it brings. The sun currently has five labeled active regions on its Earth-facing side.

Sun activity for July 16, 2023: Cannibal CME and backside activity
The July 14 dark spray coronal mass ejection (CME) event is expected to overtake a July 15 CME. Therefore, this is often called a cannibal CME. In this case, neither event has a strong Earth-directed component. But the interaction has a good chance of knocking more of the plasma cloud into the sun-Earth line. If it happens, it would create a stronger Earth-directed component (stronger than zero). And that could means auroras. Meanwhile, on the sun, sunspot region AR3363 has kept its delta region. And now the previously active AR3372 has developed more magnetic complexity, a beta-gamma-delta configuration. The more complex the sunspot, the greater the potential for large flares. On the backside of the sun, a large region is still indicated by heliosiesmology. The region may be the origin of several (at least three) large CME related waves from the backside. These are apparent in the SUVI imagery on the west limb (edge) of the sun.
Last 24 hours: Sun activity is moderate with an M1.1 flare from AR3372 at 8:16 UTC on July 16. This flare caused an R1 radio blackout over the sun facing side of Earth. The sun also produced 14 C flares between 11 UTC yesterday and 11 UTC today. As of then, the sun currently has six labeled active regions on its Earth-facing side.
The sun in recent days







More sun images from our community
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Bottom line: Sun activity for July 20, 2023. A big blast on the northwest quadrant produced an eye-catching prominence and CME. Meanwhile sunspot AR3363 still M flaring from beyond the solar horizon on the southwest.
