Geomagnetic storms – The Watchers

CH HSS sparks G2 – Moderate geomagnetic storm

Teo Blašković — Fri, 13 Jun 2025 09:10:25 +0000

Elevated geomagnetic activity was recorded on Earth on June 13, 2025, due to the waning effects of a negative polarity coronal hole high-speed stream and possible transient effects.

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G4 – Severe geomagnetic storm watch issued for June 2 following strong Earth-directed CME

Teo Blašković — Sat, 31 May 2025 19:51:03 +0000

The U.S. Space Weather Prediction Center (SWPC) issued a G4 - Severe geomagnetic storm watch for June 2, 2025, following the eruption of a powerful, Earth-directed coronal mass ejection (CME) associated with a long-duration M8.1 solar flare from Active Region 4100. The CME is forecast to arrive at Earth late on June 1, with geomagnetic storm conditions expected to intensify through June 2.

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Negative polarity CH HSS triggers G3 – Strong geomagnetic storm

Teo Blašković — Thu, 29 May 2025 09:57:05 +0000

A G3 - Strong geomagnetic storm was observed at 02:16 UTC on May 29, 2025, triggered by the arrival of a negative polarity coronal hole high-speed stream at Earth. Coronal hole high-speed streams, and their associated transition zones called co-rotating interaction regions (CIRs), can create CME-like shock waves that are capable of producing strong geomagnetic disturbances and widespread auroras.

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CME impacts Earth sparking widespread aurora, G3 – Strong storm Watch in effect for April 16

Teo Blašković — Wed, 16 Apr 2025 10:36:31 +0000

A coronal mass ejection produced by a filament eruption on April 13 impacted Earth's magnetic field at 16:37 UTC on April 15, sparking a G2 - Moderate geomagnetic storm. A G3 - Strong geomagnetic storm watch is in effect for April 16 due to the anticipated arrival of additional CMEs.

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Large coronal hole facing Earth, G2 – Moderate geomagnetic storm

Teo Blašković — Wed, 26 Mar 2025 16:38:15 +0000

Earth is currently experiencing heightened solar wind conditions and geomagnetic storming due to the passage of a co-rotating interaction region (CIR) ahead of a high-speed stream from a large coronal hole in the southern hemisphere.

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G1 – Minor geomagnetic storm watch in effect

Rishav Kothari — Thu, 30 Jan 2025 22:22:21 +0000

A G1 - Minor geomagnetic storm watch is in effect for January 31 and February 1, 2025, due to a coronal hole high-speed stream (CH HSS) influence coupled with the potential arrival of a CME.

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Two CMEs impact Earth, producing G4 – Severe geomagnetic storm

Teo Blašković — Thu, 02 Jan 2025 17:44:06 +0000

Two coronal mass ejections (CMEs) produced on December 29, 2024, impacted Earth on December 31, causing G4 - Severe geomagnetic storm on January 1, 2025. A slow return to nominal levels is expected by late on January 2. Late on January 3 to early on January 4, a potential glancing blow from the January 1 CME is likely to cause another enhancement.

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Two CMEs to impact Earth, G3 – Strong Geomagnetic Storm Watch in effect for December 31

Teo Blašković — Mon, 30 Dec 2024 11:11:28 +0000

At least two coronal mass ejections (CMEs) are heading toward Earth, with impacts expected on December 31 and January 1, 2025. The first CME -- much stronger, was produced by a filament eruption associated with an M2.0 flare at 04:30 UTC on December 29 from Active Region (AR) 3939. This resulted in an asymmetric, partial-halo CME first seen in NASA coronagraph imagery at approximately 06:24 UTC.

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CME impacts Earth, sparking G1 geomagnetic storm

Teo Blašković — Tue, 17 Dec 2024 10:37:17 +0000

A coronal mass ejection (CME) produced on December 13, 2024, impacted Earth at 05:19 UTC on December 17, sparking G1 - Minor geomagnetic storming. The K-index reached 5 at 08:07 UTC, with effects limited to areas poleward of 60 degrees geomagnetic latitude. Enhanced solar wind conditions, driven by a positive polarity coronal hole high-speed stream (CH HSS), are expected to continue through December 18. Meanwhile, solar activity remains low, with a 30-40% chance of M-class flares and a 5% chance of X-class flares through December 19.

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Fast CME produced by X1.8 solar flare impacts Earth, producing G4 – Severe geomagnetic storm

Teo Blašković — Thu, 10 Oct 2024 16:48:59 +0000

Coronal mass ejection (CME) produced by X1.8 solar flare on October 9, 2024, impacted Earth at 15:15 UTC on October 10, at nearly 2.4 million km/h (1.5 million miles per hour), triggering G4 - Severe geomagnetic storm.

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