A series of M-class flares — all from Region 4479 — pushed solar activity to high levels this week. The largest of the flares was an M3.5 on July 1.
An earlier flare from this region, M1.3 accompanied by a 1N H-alpha flare which peaked late July 1, appears to have been associated with dimming and a coronal mass ejection (CME) first identified in CCOR-1 imagery. Initial analysis suggests the CME has an Earth-directed component, although the speed derived from the available imagery was only 300-450 km/s. Further analysis is needed to increase confidence.
Flux emergence and some consolidation around the leader and trailer spots was observed in Region 4479 during the period. Region 4478 produced an M8.5/2b flare on July 1 following occasional C-class flaring. This region also exhibited flux emergence in the intermediate spots and around the leader spot. Finally, Region 4480 was quiescent although some intermediate spots developed.
Solar activity is likely to decrease to moderate levels (R1-R2, minor-moderate) with a slight chance for X-class flares (R3-strong), particularly from Region 4479.
Solar wind parameters were enhanced with CME passage. Solar wind speeds have ranged from approximately 360 – 425 km/s. The CME from June 30 is expected to arrive early on July 3, bringing disturbed solar wind conditions that are expected to last into July 4. There is enough uncertainty around the CME timing that an arrival mid-to-late on July 2 is possible.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere, July 2, 2026, by F. K. Janda, OK1HH:
Near the extensive active region AR4478, which the Solar Orbiter had been observing for several days before it rose on the southeastern limb of the solar disk, a small region, AR4479, was initially discovered. Both regions grew rapidly in the following days, while the configuration of their magnetic fields indicated nearby increased eruptive activity. High-energy flares occurred primarily on and after June 30, while some were accompanied by CMEs.
Because the CMEs occurred near the solar central meridian, Earth was strongly affected by an intensified solar wind. Shortwave propagation conditions were favorable during the so-called positive phase of the disturbance on June 30, but very unfavorable during the negative phase on July 1. A similar pattern may recur in the coming days!
The predicted Planetary A Index for July 7 to July 12 is 14, 5, 5, 12, 15, 12, and 8, with a mean of 10.1. The predicted Planetary K Index is 4, 2, 2, 4, 4, 4, and 3, with a mean of 3.3. Predicted 10.7 centimeter flux is 130, 125, 125, 125, 120, 125, and 120, with a mean of 124.3.
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere . Information and
tutorials on propagation can be found at, http://k9la.us/ .
Also, check this:
https://bit.ly/3Rc8Njt
“Understanding Solar Indices” from September 2002 QST.