Series of CMEs expected to impact Earth, G2 - Moderate geomagnetic storm watch in effect

Series of CMEs expected to impact Earth, G2 - Moderate geomagnetic storm watch in effect

A series of coronal mass ejections (CMEs) produced by Regions 2887 and 2891 over the past couple of days will likely impact Earth by late November 3 to early November 4, causing additional enhancements to the solar wind environment already enhanced due to coronal hole influence. CME effects are expected to persist through November 5.

As a result, SWPC has issued a G2 - Moderate geomagnetic storm watch for November 4.

Potential impacts:
(area of impact primarily poleward of 55 degrees Geomagnetic Latitude)

Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.

Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.

Radio - HF (high frequency) radio propagation can fade at higher latitudes.

Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

Quiet to unsettled geomagnetic field levels are expected for most of November 3 ahead of the November 2 CMEs.1, 2

G1 - Minor geomagnetic storm conditions are likely, with a chance for G2 - Moderate storm levels, late on November 3 to early on November 4 due to combined CME/CH HSS activity.2

Unsettled to active levels are expected on 05 Nov as CH HSS and CME effects wane.


  • A geomagnetic sudden impulse was detected at 19:57 UTC, signaling the arrival of CME to Earth.
Space Weather Message Code: SUMSUD
Serial Number: 232
Issue Time: 2021 Nov 03 1957 UTC
SUMMARY: Geomagnetic Sudden Impulse
Observed: 2021 Nov 03 1957 UTC
Deviation: 21 nT
Station: FRD
NOAA Space Weather Scale descriptions can be found at
  • Series of CMEs impact Earth, sparking G3 - Strong geomagnetic storming - The Watchers


1 Long-duration M1.7 solar flare erupts from geoeffective AR 2981, CME impact expected - The Watchers

2 Forecast Discussion Issued: 2021 Nov 03 1230 UTC - Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center

Featured image credit: ESA/NASA, Helioviewer, TW


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