Solar wind
speed: 393.0 km/sec
density: 0.93 protons/cm3
Updated: Today at 1126 UT

X-ray Solar Flares
6-hr max: M1 1812 UT Apr21
24-hr: M1 1812 UT Apr21
Updated: Today at: 2330 UT

Sun's Eruption Could Trigger Earth-Directed CME

NASA's Solar Dynamics Observatory has detected a significant M2-class solar eruption, as a magnetic filament snaking across the sun's southern hemisphere erupted today.

The eruption may have launched a coronal mass ejection (CME) towards Earth, which is further supported by Type II and Type IV solar radio bursts detected by the US Air Force.

These radio bursts are natural emissions produced by shock waves preceding the CME as it passes through the sun's atmosphere, with drift rates in the Type II burst suggesting a CME velocity of about 580 km/s (1.3 million mph).

https://spaceweather.com/images2023/21apr23/filament_anim_teal_crop_strip.gif

Slow-Moving CME Could Trigger Minor Geomagnetic Storm Today

NOAA forecasters have issued a warning of a possible minor G1-class geomagnetic storm today, April 21st, as a coronal mass ejection (CME) is expected to impact Earth's magnetic field.

The CME was ejected from the sun on April 16th, and its unusually slow pace in crossing the sun-Earth divide (5 days) suggests that it is unlikely to cause anything more than a minor storm.

While this may lead to minor fluctuations in power grids and satellite communication, it is not expected to cause significant disruptions. Stay tuned for further updates on the status of the storm.

Solar wind
speed: 524.4 km/sec
density: 7.68 protons/cm3
Updated: Today at 0540 UT

X-ray Solar Flares
6-hr max: C2 1305 UT Apr24
24-hr: C2 1305 UT Apr24
Updated: Today at: 1745 UT

THE STORM IS SUBSIDING: A severe G4-class geomagnetic storm that sparked auroras over Europe, China, and most of the United States on April 23-24 is subsiding. The storm was caused by a CME hitting Earth's magnetic field. Minor (G1) to moderate (G2) geomagnetic storm remain possible on March 24-25 as Earth exits the CME's wake.

Solar wind
speed: 491.4 km/sec
density: 3.15 protons/cm3
Updated: Today at 0431 UT

X-ray Solar Flares
6-hr max: C2 1059 UT May02
24-hr: C7 2232 UT May01
Updated: Today at: 1635 UT

A MONTH OF SUNSPOTS: April 2023 was a busy month on the sun, with the average sunspot number (96) exceeding official forecasts for the 26th month in a row. To illustrate this development, Senol Sanli of Bursa, Turkey, stacked 30 daily sun images from NASA's Solar Dynamics Observatory to create an April montage:

https://spaceweather.com/images2023/01may23/april_strip.jpg

"This single image shows every sunspot group in April," says Sanli. "It includes every numbered active region from AR3267 to AR3292."

The profusion of sunspots reinforces a growing consensus that Solar Maximum may be coming earlier than expected--perhaps as soon as late 2023. The peak could bring 50% to 100% more sunspots than we are seeing today, cementing Solar Cycle 25 as an above-average cycle. If so, Sanli's monthly sunspot montage might become quite congested indeed. Stay tuned.

MINOR GEOMAGNETIC STORM WATCH: NOAA forecasters say that minor G1-class geomagnetic storms are possible on May 2nd and 3rd due to the collective effect of several faint CMEs that left the sun over the weekend. They were launched into space by multiple eruptions from sunspot AR3288 and nearby magnetic filaments. A series of near misses and weak impacts could add up to high-latitude auroras in the next 48 hours.

Solar wind
speed: 465.9 km/sec
density: 4.14 protons/cm3
Updated: Today at 0550 UT

X-ray Solar Flares
6-hr max: M2 1350 UT May03
24-hr: M7 1045 UT May03
Updated: Today at: 1755 UT

A SUDDEN DECREASE IN COSMIC RADIATION: Last month, during the late hours of April 23rd, a CME hit Earth's magnetic field. The impact sparked a severe geomagnetic storm with auroras so bright they could be seen as far south as Texas. Invisible to the human eye, something else happened. There was a sudden decrease in cosmic radiation:

https://spaceweather.com/images2023/02may23/forbush_data_crop2_strip.jpg

In a matter of hours, cosmic rays peppering Earth's atmosphere dropped to their lowest levels since 2015. Neutron monitors in Oulu, Finland, detected the drop, which lasted for days.

This is called a "Forbush decrease," named after American physicist Scott Forbush who studied cosmic rays in the early 20th century. It happens when a coronal mass ejection (CME) sweeps past Earth and pushes galactic cosmic rays away from our planet. It sounds counterintuitive, but big solar storms can cause sharp decreases in space radiation.

This Forbush decrease is over, but more are in the offing. Solar Max is coming and soon the sun will be hurling many more CMEs in our direction. Their cumulative effect could create a sustained decrease in cosmic radiation, lowering dose rates for astronauts and air travelers.

INTENSIFYING SOLAR ACTIVITY: Sunspot complex AR3293-3296 is crackling with strong M-class solar flares--six of them today so far. This short movie from NASA's Solar Dynamics Observatory includes the stongest, an M7-class explosion:

https://spaceweather.com/images2023/03may23/m7_teal_strip_opt.gif

Pulses of extreme UV radiation are causing a rolling series of shortwave radio blackouts around the dayside of Earth. Loss of signal has been greatest over Africa where ham radio operators may have noticed fade-outs at all frequencies below 30 MHz.

Solar wind
speed: 476.7 km/sec
density: 7.17 protons/cm3
Updated: Today at 0320 UT

X-ray Solar Flares
6-hr max: C4 1214 UT May16
24-hr: C4 1214 UT May16
Updated: Today at: 1525 UT

MINOR CME IMPACT STILL POSSIBLE TODAY: NOAA forecasters say that a CME could hit Earth's magnetic field midday (UT) on May 16th. Relatively faint and slow-moving, it was hurled into space on May 12th by an erupting filament of magnetism in the sun's southern hemisphere. No more than minor G1-class geomagnetic storms are expected.