Sun news: Fast solar wind still stirring Earth’s magnetic field

Sun news September 26: Fast solar wind still stirring Earth’s magnetic field

Today’s top story: The fast solar wind from a coronal hole that arrived yesterday is still going. It held conditions at Kp 4 for most of the past day, meaning Earth’s magnetic field has been experiencing active, unsettled conditions, sitting just below the geomagnetic storm threshold. Still, there were auroral displays at high latitudes last night. And we hear from many people who say that this sort of activity from the sun causes headaches, mood swings, and sleep disturbances. Is it true? What does the science say? EarthSky’s Deborah Byrd and heliophysicist C. Alex Young had a fascinating discussion about this subject in this video.

Past 24 hours on the sun

(11 UTC September 25 – 11 UTC September 26)

Flare activity: It’s been a quiet week on the sun. Solar activity stayed at very low levels over the past day, with mostly B flares and just one C flare. The tally from the past day was one C-class and four B-class (weak).

• Strongest flare: A C1.2 from AR4534, peaking at 18:30 UTC on September 25.
• Lead flare producer: AR4536 topped the list again, this time with two B flares.

Sunspot regions: We saw a spotless sun for a couple of days earlier this week. Then, at one point, as many as eight numbered active regions popped up on the Earth-viewed disk. All were short-lived, lasting just a few days, including one region (AR4536) with a promising beta-delta magnetic complexity. Over the past day, the side of the sun facing Earth has shown five numbered sunspot regions. No newcomers appeared over the past day. Notably, every numbered region now shows either an alpha or a beta configuration, since AR4536 lost its delta.

• AR4533 (beta): This region held its beta configuration and produced no flares.
• AR4535 (beta): This region produced one faint B flare.
• AR4536 (alpha): This region lost its delta completely. In fact, its configuration dropped from beta to a simpler alpha. It still produced two B flares.
• AR4537 (beta): This region produced one B flare.
• AR4542 (alpha): This region produced no flares.

Blasts from the sun? Observers spotted no Earth-directed coronal mass ejections (CMEs) in available coronagraph imagery during the period.

Past 24 hours in space weather

Solar wind: Solar wind speeds kept climbing from moderate to moderate-high levels through the period. Continued effects from the coronal hole high-speed stream drove this environment. By the end of the period, though, speeds began to decline as the stream waned.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field (IMF) started at strong levels. It then slowly eased to weak strength by the end of the period. Meanwhile, the north-south component (Bz) showed a few northward peaks. For most of the period, however, it pointed south. Those long southward stretches helped magnetic coupling with Earth’s field, which is why auroras appeared at high latitudes.

Earth’s magnetic field: Geomagnetic activity ranged from quiet-to-active levels, with the Kp index at 2 to 4. Kp 4 dominated, holding for nearly four three-hour synoptic periods. Conditions reached that threshold several times, starting at 11 UTC on September 25. At the time of this writing, the Kp index sits right at level 4.

What’s ahead? Sun–Earth forecast

Flare activity forecast: Forecasters notably lowered their expectations for solar activity through the weekend. The main reason is AR4536 losing its beta-delta complexity. As a result, the chance of moderate (M-class) activity dropped to 10% today, down from 20% yesterday. Meanwhile, chances for X-class (strong) flares remain minimal. AR4537 might contribute the occasional minor C flare.

Geomagnetic activity forecast:

• September 26: Expect active periods to continue during the day, as the coronal hole’s fast solar wind keeps affecting Earth before it starts to wane. Active intervals may reach Kp 4.
• September 27: Expect quiet to unsettled conditions, with isolated active periods up to Kp 4, as the fast solar wind begins to fade. Still, thanks to the Russell-McPherron effect, auroral displays remain possible even at Kp 4. Keep watching, aurora observers!
• September 28: Anticipate mostly quiet levels.

Sun news September 25: Fast wind arrives, auroras up north

The anticipated stream of fast solar wind from a coronal hole arrived over the past day. However, it only stirred Earth’s magnetic field to active levels, just shy of the expected G1 (minor) geomagnetic storm. However, far-northerly latitudes still saw auroras, as you can see above. That was likely helped by the Russell-McPherron effect, which explains why we see more auroras around the equinoxes.

Past 24 hours on the sun

(11 UTC September 24 – 11 UTC September 25)

Flare activity: Solar activity continued at low levels over the past day. Notably, flare production dropped to just three flares, compared to six yesterday. This period’s tally: one C-class and two B-class (weak).

• Strongest flare: A C1.2 from AR4536, peaking at 2:44 UTC on September 25.
• Lead flare producer: AR4536 topped the list with two flares: the period’s only C flare plus one B flare.

Sunspot regions: Currently, the Earth-viewed solar disk holds seven numbered sunspot regions. A newcomer, AR4542 in the southeast, received its number today. Moreover, one region now shows a delta magnetic complexity: AR4536.

• AR4533 (beta): This region showed some growth. Its complexity also increased, from alpha yesterday to beta today.
• AR4535 (beta): This region gained some strength during the period. It produced one faint B flare.
• AR4536 (beta-delta): This region kept growing and developed a delta magnetic complexity. It also produced the period’s only C flare. That delta makes it a candidate for stronger flares. This guy is worth watching.
• AR4537 (beta): This region showed growth but stayed stable, with no flares.
• AR4538 (beta): This region stayed stable and produced no flares.
• AR4539 (alpha): This region stayed stable and produced no flares.
• AR4542 (alpha): This region emerged from nowhere in the middle of the southeast quadrant. It looks stable so far, with no flares.

Blasts from the sun? Observers spotted no Earth-directed coronal mass ejections (CMEs) in available coronagraph imagery during the period.

Past 24 hours in space weather

Solar wind: Solar wind speeds increased from low to moderate, then moderate-high levels through the period. The arrival of a coronal hole high-speed stream drove this rise.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field (IMF) increased to moderate and then strong levels. At the time of this writing, it sits at moderate strength. Meanwhile, the north-south component (Bz) pointed southward for the entire period. As always, long southward stretches like this help magnetic coupling with Earth’s field. So auroras could follow under these conditions.

Earth’s magnetic field: Geomagnetic activity ranged from very quiet to active levels, with the Kp index at 0 to 4. At the time of this writing, the Kp index sits just below level 4.

Sun news September 24: Fast solar wind has started to arrive

A stream of fast solar wind from a coronal hole has started to reach Earth’s magnetic field. Solar wind speeds have already climbed to moderate-low levels, and the trend points higher. As a result, we could see G1 (minor) geomagnetic storms today.

The source is the large coronal hole we’ve been watching. It launched this fast wind straight toward Earth a couple of days ago, and that wind is only now reaching us. So Earth’s magnetic field should stay disturbed at active levels through tomorrow, September 25. That means auroral displays are possible. Clear skies!

Past 24 hours on the sun

(11 UTC September 23 – 11 UTC September 24)

Flare activity: Solar activity stayed at low levels. Over the past day, the sun produced six flares: three C-class and three B-class (weak).

• Strongest flare: A C1.7 from AR4537, peaking at 11:31 UTC on September 23.
• Other notable flares: A C1.1 from AR4538 at 15:32 UTC on September 23. Then a C1.0 from AR4536 at 21:25 UTC the same day. The rest were faint B flares.
• Lead flare producer: AR4537 and AR4538 ended tied at the top of the list, with two flares each.

Sunspot regions: From Earth, we can see seven numbered sunspot regions on the solar disk. No new regions appeared today.

• AR4533 (alpha magnetic complexity): This region sits in the southeast quadrant. It showed minor activity.
• AR4534 (beta): This region showed signs of decay. It produced no flares.
• AR4535 (beta): This region gained some strength during the period. It produced one faint B flare.
• AR4536 (beta): This region kept growing. It also produced one C flare.
• AR4537 (beta): This region fired the strongest flare of the period, the C1.7.
• AR4538 (beta): This region grew as well. It ranked among the period’s C flare producers.
• AR4539 (beta): This region stayed stable and produced no flares.

Blasts from the sun? Observers spotted no Earth-directed coronal mass ejections (CMEs) in available coronagraph imagery during the period.

Past 24 hours in space weather

Solar wind: Solar wind speeds increased from low to moderate-low levels through the reporting period. The trend suggests they may keep climbing. The arrival of a coronal hole high-speed stream is driving the rise.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field increased to moderate strength. Meanwhile, the north-south component (Bz) pointed completely northward during the first half of the period. Then, around 0 UTC this morning, it turned south. It has stayed south through the time of this writing. As always, a southward Bz helps magnetic coupling with Earth’s field. So auroras could follow under these conditions.

Earth’s magnetic field: Geomagnetic activity ranged from very quiet to unsettled levels, with the Kp index at 0 to 3. At the time of this writing, the Kp index sits at level 2.

Sun news September 23: Solar wind gust could spark auroras

NOAA’s Space Weather Prediction Center has issued a G1 (minor) geomagnetic storm alert today due to a stream of fast solar wind from a coronal hole reaching Earth. The first signs of that high-speed solar wind should show up later today, and effects might extend through September 24 and 25. Could this trigger auroras? Well, auroras are more likely around equinoxes, and the September equinox arrived just yesterday evening … so possibly! Read about aurora seasons here.

Past 24 hours on the sun

(11 UTC September 22 – 11 UTC September 23)

Flare activity: Solar activity stayed at low levels over the past day. However, flare production increased compared to the previous day. The sun produced nine flares, versus four yesterday. This period’s tally: three C-class and six B-class (weak).

• Strongest flare: A C2.4 from AR4534, peaking at 17:20 UTC on September 22.
• Other notable flares: A C1.1 from AR4536 at 17:58 UTC on September 22. Then a C1.4 from AR4535 at 6:21 UTC on September 23. The rest were faint B flares.
• Lead flare producer: AR4535 led the list with four flares during this period: one C flare plus three B flares.

Sunspot regions: The Earth-facing solar disk now holds eight numbered sunspot regions. Three newcomers received their numbers during the past day: AR4538, AR4539, and AR4540.

• AR4533 (alpha magnetic configuration): This region sits in the southeast quadrant. It showed minor activity.
• AR4534 (beta): This region remains a flare producer. It sparked one of the period’s C flares plus a B flare. However, it appears to have lost the delta magnetic configuration it developed earlier this week.
• AR4535 (beta): This region stayed active throughout the period. It produced one of the three C flares.
• AR4536 (beta): This region has continued growing since it appeared yesterday. Today it produced one C flare.
• AR4537 (beta): This region showed an increase in magnetic complexity. It produced one B flare.
• AR4538 (beta), AR4539 (beta), and AR4540 (alpha): These regions received their numbers this period but stayed stable. Only AR4539 produced a B flare.

Blasts from the sun? Analysts detected no Earth-directed coronal mass ejections (CMEs) during the period.

Past 24 hours in space weather

Solar wind: Solar wind speeds averaged low levels through the reporting period, under the waning influence of a previous coronal hole high-speed stream. For now, there’s no significant space weather to report. But that may change in the next few hours, with the arrival of fast solar wind from a newer coronal hole.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field stayed weak. Meanwhile, the north-south component (Bz) kept shifting between southward and northward in short intervals for most of the period. Then, at around 2:30 UTC this morning, it turned north and has held there until the time of this writing. Short-lived southward Bz doesn’t help magnetic coupling with Earth’s field, so auroras may not occur under these conditions. All of that may change in the coming hours.

Earth’s magnetic field: Geomagnetic activity remained at very quiet levels. The Kp index held at 0 for most of the period.

Sun news September 22: 3 events to notice on today’s sun

It’s almost the equinox; the sun crosses the celestial equator at 7:05 p.m. CDT today (00:05 UTC on September 23). And today three sun events join the equinox party. They are: the return of sunspot regions to the Earth-facing side of our star, the return of C-class (common) flares and a coronal hole reaching geoeffective position. Read about these events below. All three could participate in producing auroras in the coming days, which, by the way, have a their own favorable season of activity, twice a year, at the spring and fall equinoxes. Why an aurora season? It’s due to magnetism, geometry and something called the Russell-McPherron effect. Read about aurora seasons here. Happy equinox!

Past 24 hours on the sun

(11 UTC September 21 – 11 UTC September 22)

Flare activity: Solar activity continued at low levels over the past day. But we did have a C flare! The sun produced 4 flares during the period: 1 C-class and 3 B-class (weak).

• Strongest flare: A C2.0 from AR4536, peaking at 4:51 UTC on September 22.
• Other notable flares: A B6.8 at 11:17 UTC on September 21 from AR4535. Active region AR4534 produced the other two B flares of the period, a B6.5 at 23:57 UTC on September 21 and a B6.6 at 3:09 UTC on September 22.
• Lead flare producer: AR4534 continues to dominate, producing 2 of the 4 flares of the period. AR4535 and AR4536 contributed the rest.

Sunspot regions: Currently the Earth-facing side of our sun is populated with 5 numbered sunspot regions. Two newcomers received their numbers during the past day, AR4536 and AR4537.

• AR4533 (alpha) sits in the southeast quadrant. It showed minor activity.
• AR4534 (beta) lost its delta during the period and now shows a simpler beta configuration. It remains lead flare producer.
• AR4535 (alpha), a newcomer, produced a B flare today.
• Two additional regions sit on the disk. Newcomer AR4536 (beta) in the center of the solar disk, showed rapid growth and produced the strongest flare. AR4537 (beta) in the northwest stayed small, simple and stable throughout the period.

Blasts from the sun? Analysts detected no Earth-directed coronal mass ejections (CMEs) during the period.

Past 24 hours in space weather

Solar wind: The solar wind speeds gradually decreased to moderate-low and low levels through the reporting period. This decline fits the waning influence of a previous coronal hole high-speed stream.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field was weak. Meanwhile, the north-south component (Bz) showed southward directions for most of the period. At around 4 UTC this morning, the Bz component turned north to stay there until the time of this writing. A continued south Bz contributes to magnetic coupling with Earth’s field and therefore auroras.

Earth’s magnetic field: Geomagnetic activity remained at quiet levels. Kp index 0 – 2. At the time of this writing the Kp index sits just above 0 level.

Sun news September 21: Promising sunspot group AR4534 is growing

The sun is keeping a low profile right now. Solar activity stayed at low levels over the past 24 hours, with only C-class flares popping off from a couple of active regions. But one region near the solar disk’s center is getting more interesting by the day. The region, AR4534, has been developing rapidly. Observers note a proliferation of sunspots and a complex delta magnetic configuration forming. The greater a sunspot group’s magnetic complexity, the greater the chance that it will fire off some big flares. We’ll keep watching this region.

Past 24 hours on the sun

(11 UTC September 20 – 11 UTC September 21)

Flare activity: Solar activity stayed low. The sun produced 11 flares during the period: 3 C-class and 8 B-class.

• Strongest flare: A C3.7 from AR4534, peaking at 22:34 UTC on September 20.
• Other notable flares: Two more C-class flares occurred, both from AR4534: a C1.1 peaking at 1:13 UTC and a C1.2 peaking at 6:29 UTC on September 21.
• Lead flare producer: AR4534 dominated, producing 9 of the 11 flares. AR4532 and AR4533 contributed the rest, all B-class.

Sunspot regions: Six numbered sunspot regions sit on the visible disk. One newcomer, AR4535, received its number during the period.

• AR4532 (beta): This region sits in the southwest quadrant. It showed minor growth during the period. It also produced one B7.8 flare, peaking at 21:43 UTC on September 20.
• AR4533: This region produced two B-class flares during the period, a B8.0 and a B5.0. Otherwise, it stayed stable.
• AR4534 (beta-delta): The star of the show sits near the disk’s center. It showed minor growth and a rapidly developing, increasingly complex magnetic structure. Forecasters note a proliferation of spots throughout the region. Moreover, a delta configuration has formed within its northern intermediate portion. AR4534 produced 9 of the period’s 11 flares, including the strongest, the C3.7.
• AR4535 (alpha): A newcomer! This region rotated into view in the northeast quadrant. Its alpha classification means it has a simple magnetic structure for now.
• Two additional regions sit on the disk. They stayed small, simple, and stable throughout the period.

Blasts from the sun? Analysts detected no Earth-directed CMEs during the period.

Past 24 hours in space weather

Solar wind: The solar wind environment remains undisturbed. Speeds gradually decreased to normal through the reporting period. This decline fits the waning influence of a previous coronal hole high-speed stream.

Bt, Bz and magnetic coupling: The total interplanetary magnetic field (Bt) was weak. Meanwhile, the north-south component (Bz) varied between northward and southward directions. That weak, fluctuating Bz offered minimal magnetic coupling with Earth’s field.

Earth’s magnetic field: Geomagnetic activity stayed quiet to unsettled. The Kp index reached up to 3.

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Bottom line: Sun news September 26, 2026: Fast solar wind continued disturbing Earth’s magnetic field up to active levels and triggering auroras at northern latitudes.

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