Multiple Earth-directed CMEs, G2 – Moderate geomagnetic storm predicted for August 18

A G2 – Moderate geomagnetic storm watch is in effect for August 18, 2022, as a result of CME activity on August 14 and 15 coupled with a recurrent, negative polarity CH HSS.

• Increased activity continued into August 16, with C8.4 and M5.0 from AR 3078 located at the center of the solar disk.
• There is a chance for X-class solar flares through August 18 or even stronger geomagnetic storms.

Solar activity reached moderate levels over the past 36 hours, with 5 M- and numerous C-class flares.

A geoeffective Active Region 3078 (‘Beta-Gamma-Delta’), the most magnetically complex and the most active spot group on the visible disk, produced an M1.0 flare at 14:36 UTC on August 15, M2.7 at 16:54 UTC, M1.1 at 21:53 UTC and M5.0 at 07:58 UTC on August 16.

After exhibiting an overall decay, Region 3079 (‘Beta’) began to show signs of minor redevelopment near its intermediate and trailer spots on August 15. It produced an M0.9 flare at 17:35 UTC, as well as multiple C-class flares.

A filament eruption, centered near S21W43, began after 04:00 UTC on August 15, producing a long-duration X-ray event that reached C3 at 05:22 UTC.

Subsequent coronagraph imagery indicated a coronal mass ejection (CME) signature from the eruption that, following further analysis, is likely to catch the partial-halo CME from August 14, and arrive at Earth simultaneously.¹

Solar wind enhancements are expected to start on August 17 as a recurrent, negative polarity coronal hole high speed stream (CH HSS) moves into geoeffective position.

On August 18, this CH HSS influence is likely to be further enhanced as a pair of CMEs from August 14 and 15 combine with the HSS, likely elevating wind speeds in excess of 600 km/s and causing G2 – Moderate magnetic storm levels. As a result, a G2 – Moderate Geomagnetic Storm Watch is now in effect for August 18.

Increased activity continued into August 16, with C8.4 and a very nice CME from AR 3078 at 00:13 UTC.

The strongest solar flare through 08:35 UTC today was M5.0 at 07:58 UTC, also from AR 3078.

Keep in mind that this is now a geoeffective region, so any CME produced would likely be Earth-directed.

With an already disturbed geomagnetic field, there is a chance for even stronger geomagnetic storms than G2 when they arrive.

There is also a slight chance for X-class flares through August 18.

References:

¹ Forecast Discussion Issued: 2022 Aug 16 0030 UTC. Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center

Featured image credit: NASA SDO/AIA 304, The Watchers