{"id":799922,"date":"2025-12-29T12:45:39","date_gmt":"2025-12-29T17:45:39","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=799922"},"modified":"2025-12-29T12:45:39","modified_gmt":"2025-12-29T17:45:39","slug":"earth-directed-cme-from-m4-2-flare-forecast-to-produce-g1-geomagnetic-storm-on-new-years-day","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=799922","title":{"rendered":"Earth-directed CME from M4.2 flare forecast to produce G1 geomagnetic storm on New Year\u2019s Day"},"content":{"rendered":"


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A coronal mass ejection (CME) produced by an M4.2 solar flare from Active Region 4317 at 22:39 UTC on December 28 is expected to cause a glancing impact on Earth\u2019s magnetic field late on December 31 into early January 1, triggering a G1 \u2013 Minor geomagnetic storm at the beginning of the new year.<\/p>\n

This is the highest level predicted through the three-day outlook.<\/p>\n

Modeling of the CME propagation suggests that the plasma cloud associated with the M4.2 event will only partially intersect Earth\u2019s orbit, producing an indirect or grazing encounter rather than a full impact.<\/p>\n

Although the CME is not Earth-directed in its entirety, its flank is expected to merge with a negative-polarity coronal hole high-speed stream already moving through the inner heliosphere.<\/p>\n

It is this interaction that may enhance geomagnetic activity to minor storm levels.<\/p>\n

Image credit: SWPC<\/figcaption><\/figure>\n

Potential impacts are expected primarily at geomagnetic latitudes poleward of 60\u00b0. Weak induced current fluctuations in power grids are possible, while minor effects on satellite operations may occur. Aurora may become visible across high-latitude regions, including parts of northern Michigan and Maine in the United States.<\/p>\n

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The latest M4.2 flare in AR 14317 was eruptive with some coronal waves. But this animation indicates the eruption was largely directed to west, consistent with coronagraph imagery \u2013 weak glancing blow at best. pic.twitter.com\/7EOuFZZTvV<\/a><\/p>\n

\u2014 Halo CME (@halocme) December 29, 2025<\/a><\/p><\/blockquote>\n<\/div>\n<\/figure>\n

Solar activity remained at moderate levels on December 28\u201329. Region 4317 produced the aforementioned M4.2 flare and a secondary C8.9 flare, while Region 4325 generated M1.3 and M1.0 flares as it exhibited rapid growth and magnetic complexity.<\/p>\n

Region 4321 showed signs of restructuring as it approached the west limb but remained relatively quiet. Other active regions were stable or in decay.<\/p>\n

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\"sunspots\"sunspots
Sunspots on December 29, 2025. Credit: NASA SDO\/HMI<\/figcaption><\/figure>\n<\/div>\n

The solar wind during the past 24 hours reflected near-background conditions, with speeds between 450 and 500 km\/s, total magnetic field strength of 3\u20138 nT, and Bz components fluctuating between +5 and \u22125 nT.<\/p>\n

SWPC forecasts background conditions to continue through December 30, followed by enhanced parameters on December 31 as the coronal hole and CME influence reach Earth.<\/p>\n

The greater than 2 MeV electron flux remains at high levels, while the greater than 10 MeV proton flux continues at background intensity.<\/p>\n

No additional Earth-directed CMEs have been identified in coronagraph imagery from SOHO\/LASCO and STEREO-A spacecraft.<\/p>\n

References:<\/p>\n

1<\/sup> Forecast Discussion \u2013 SPWC \u2013 Issued at 12:30 UTC on December 29, 2025<\/p>\n


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