Sun news: Sun-stuff blast headed to Earth

Sun news August 17 (UTC): Sun-stuff blast headed to Earth

Today’s top story: Earth is bracing for a one-two punch of solar weather over the coming days. Firstly, the great rope of solar material we mentioned yesterday – a coronal mass ejection (CME) that left the sun on August 14 – should sweep past our planet later today or early tomorrow. What does that mean for us? Forecasters expect G1 (minor) to G2 (moderate) geomagnetic storms on arrival. That could bring auroras to Alaska, much of Canada, and the northern tier of the United States, from Washington state across Montana and North Dakota to northern Michigan and Maine. Across the Atlantic, Scotland and northern England may catch a show as well. And a second punch may follow. The sun launched another burst of sun-stuff with yesterday’s strongest flare, a C8.2 from AR4506. Initial analysis points to an arrival at Earth around August 20, though with only modest effects.

Past 24 hours on the sun

(11 UTC August 16 – 11 UTC August 17)

Flare activity: Solar activity remained at low levels. Observers recorded 15 C-class flares. No M-class or X-class events occurred during the period.

• Strongest flare: A C8.2 from active region AR4506 peaking at 19:01 UTC on August 16. It fell just shy of the M-class threshold. Even so, this vigorous event produced an associated CME that’s now under analysis.
• Lead flare producer: AR4506 fired 7 of the 15 flares, including the C8.2 plus several others ranging from C1.5 to C2.1.
• Other notable flares: AR4507 contributed 6 flares (C1.0 to C2.3). Its strongest was a C2.3 at 2:13 UTC on August 17.

Sunspot regions: The Earth-facing solar disk displayed five numbered sunspot regions. Notably, two now show complex magnetic configurations that can produce moderate flares.

• AR4506 (beta-gamma): The period’s most prolific flare producer. This region now sits west of the center disk. It recently developed new intermediate spots. As a result, it maintains potential for further C-class and possibly M-class flaring as it approaches the western horizon.
• AR4507 (beta-gamma): The second most active region, producing frequent low-level C-class flares. The UK Met Office noted this region grew fairly rapidly over the past 24 hours.
• AR4508 (beta): This region produced minor C-class flaring. Otherwise, it stayed stable.
• AR4510 and the remaining numbered regions stayed generally simple and stable, or in gradual decay. However, AR4510 did produce a C2.0 flare late in the period.

Blasts from the sun? Two coronal mass ejection (CME) stories are ongoing, one imminent and one developing.

• CME from August 14 (imminent arrival): The CME that departed the sun on August 14 should arrive at Earth later on August 17 or during August 18, according to NOAA SWPC and UK Met Office forecasts. Forecasters assess G1 (minor) to G2 (moderate) geomagnetic storm conditions as likely upon arrival.
• CME from August 16 (under analysis): A CME erupted at approximately 19:48 UTC on August 16, alongside the C8.2 flare from AR4506. One model run predicts Earth arrival around 12:00 UTC on August 20. Kp estimates reach 3 to 4, depending on CME orientation.

Past 24 hours in space weather

Solar wind: Solar wind conditions were slightly below the normal background level.

Bt, Bz and magnetic coupling: The interplanetary magnetic field (IMF) total strength held at low levels. Meanwhile, the Bz component was weakly variable, with no sustained southward turns.

Earth’s magnetic field: Earth’s magnetic field stayed quiet throughout the period, with Kp values ranging from 0 to 2. No geomagnetic storms occurred.

What’s ahead? Sun–Earth forecast

Flare activity forecast: Forecasters expect solar activity to remain at low levels, dominated by isolated C-class flares through August 19. A slight chance, approximately 20%, exists for R1–R2 (minor to moderate) radio blackouts from M-class flares. AR4506 and AR4507 are the likely sources, since both carry beta-gamma magnetic configurations. AR4506 is rotating toward the western limb. Meanwhile, AR4507’s recent growth bears watching.

Geomagnetic activity forecast:

• August 17: Expect quiet-to-unsettled conditions early in the day. Activity should then increase to active levels later as the August 14 CME arrives. G1 (minor) storm intervals are likely, with a chance of G2 (moderate) conditions if the CME’s magnetic field turns favorably southward. Aurora may appear over Seattle, Edinburgh, the Scottish Highlands, and similar latitudes if skies stay clear. However, cloud cover may restrict viewing across Scotland.
• August 18: Active to minor storm conditions should continue as the CME influence wanes. In addition, a possible coronal hole high-speed stream may compound the effects. G1 (minor) storm intervals are likely, with a chance of G2 (moderate) storm periods. Aurora may remain visible across northern Scotland, southern Alaska, and similar latitudes.
• August 19: Geomagnetic activity should gradually decrease to mostly quiet levels as CME effects wane. Even so, the coronal hole high-speed stream may sustain unsettled to active intervals, with a slight chance of G1 (minor) storms. Aurora visibility will retreat to higher latitudes: northern Canada, Iceland, and northern Scandinavia.
• August 20: The CME associated with the August 16 C8.2 flare may arrive around 12:00 UTC. However, with a modest predicted Kp of 3 to 4, only unsettled-to-active conditions are expected. Coronal hole fast wind effects may be waning by then.

Sun news August 16 (UTC): ‘Rope’ of sun stuff en route to Earth

A rope of solar material and magnetic fields is on its way to Earth! It left the sun on August 14, when an arching filament lifted off and hurled plasma into space. Models now show this coronal mass ejection (CME) bearing down on our planet. Forecasters expect it to arrive late on August 17. When it hits, it should spark G1 (minor) geomagnetic storms, with a chance of G2 (moderate) levels if its magnetic field turns southward on arrival. In North America, that could bring auroras to Alaska, much of Canada, and the northern tier of the United States, from Washington state across Montana and North Dakota to northern Michigan and Maine. Across the Atlantic, Scotland, northern England, and Northern Ireland might catch a show on August 17. Down south, southern New Zealand and Tasmania could see displays too. Keep in mind, though, that forecasting centers disagree on the timing. Some models point to late on August 17, while others estimate a glancing blow as late as August 19.

Past 24 hours on the sun

(11 UTC August 15 – 11 UTC August 16)

Flare activity: Solar activity remained at low to moderate levels. Observers recorded 14 C-class flares and several B-class events. No M-class or X-class flares occurred over the past day.

• The strongest flare was a C3.7 from sunspot region AR4507 at 3:31 UTC on August 16. As a C-class event, it produced no radio blackout.
• Other notable flares: NOAA logged a C3.3 from AR4508 at 8:18 UTC on August 15 as the strongest event of the earlier portion of our reporting period (11 UTC August 15 – 11 UTC August 16). There was also a C3.2 from AR4507 at 14:38 UTC on August 15, a C2.7 from AR4506 at 02:42 UTC on August 16, and a C2.3 from AR4506 at 04:37 UTC on August 16.
• Lead flare producer: Sunspot region AR4507 topped the list, firing at least 10 events (both C- and B-class), including the period’s strongest flare. Meanwhile, AR4506 contributed six C-class flares in a concentrated burst between roughly 1 and 7 UTC on August 16.

Sunspot regions: The Earth-facing solar disk displayed at least six numbered active regions. Several exhibited notable growth.

• AR4507 (with a beta magnetic configuration) was the period’s most prolific flare producer. It grew and developed new intermediate spots, with some polarity mixing, as the UK Met Office noted. This evolution bears watching for potential increases in flare productivity.
• AR4506 (beta): This region also showed growth. Moreover, it produced that notable burst of C-class flaring overnight. As it nears the western limb, foreshortening is making assessment more difficult.
• AR4508 (beta): This region produced the C3.3 flare at 08:18 UTC on August 15, the strongest event of the first half of the period.
• AR4512 (beta): This region received its number during the period. It showed growth, so forecasters will monitor it for further development.
• The remaining numbered active regions stayed mostly stable or in gradual decay. Notably, no complex magnetic configurations, beta-gamma or delta, appeared anywhere on the disk.

Blasts from the sun? Observers spotted no new Earth-directed CMEs during the period. They cataloged two CMEs from August 15: one at 11:36 UTC (402 km/s) and another at 13:48 UTC (253 km/s). But neither should impact Earth. The SIDC also identified far-sided CMEs on August 14 (CMEs 708 and 709) that pose no threat. Instead, the key CME for the forecast remains the one launched on August 14 and now heading toward Earth.

Past 24 hours in space weather

Solar wind: Solar wind conditions reflected a typical slow-wind regime throughout the period. Speeds stayed low, ranging between approximately 330 and 380 km/s.

Bt, Bz and magnetic coupling: The IMF total strength stayed under 5 nT (low) according to NOAA. Meanwhile, the Bz component was weakly variable, fluctuating between approximately -6 and +4 nT. It never held a sustained southward orientation. As a result, conditions did not favor significant aurora production.

Earth’s magnetic field: Earth’s magnetic field ranged from quiet to unsettled levels over the past 24 hours. The Kp index ranged from 0+ to 2+ globally. Conditions crossed no G-scale geomagnetic storm thresholds.

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Bottom line: Sun news August 17, 2026: A blast of solar material is set to reach Earth later today or tomorrow. G1 to G2 storms could bring auroras to Canada, the northern US, and Scotland.

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