Sunday, October 22, 2017

Moderately Strong Geomagnetic Storm Expected to Hit Earth on Wednesday

Credit: NOAA

A G2-class (moderately strong) geomagnetic storm is expected to hit Earth on Wednesday, October 25, according to a warning issued by the National Oceanic and Atmospheric Administration (NOAA). This storm could have noticeable impact on power systems, satellites and could trigger auroras seen as low as New York and Idaho.

Geomagnetic storms can increase the density and distribution of density in the upper atmosphere, causing extra drag on satellites in low-earth orbit. The local heating also creates strong horizontal variations in the in the ionospheric density that can modify the path of radio signals and create errors in the positioning information provided by GPS. While the storms create beautiful aurora, they also can disrupt navigation systems such as the Global Navigation Satellite System (GNSS) and create harmful geomagnetic induced currents (GICs) in the power grid and pipelines.

G2-class storm can cause voltage alarms and transformer damage in high-latitude power systems. When it comes to possible impact on spacecraft operations, in result of such storm, corrective actions to orientation may be required by ground control. Moderately strong geomagnetic storm can also spark auroras and cause fading of HF radio propagation at higher latitudes.

NOAA revealed that the G2-class storm on Wednesday could be preceded by a G1 (minor) storm on Tuesday. Both events are due to the anticipated arrival of a recurrent, positive polarity coronal hole high speed streams (CH HSSs).

Fast CH HSSs can impact Earth’s magnetosphere enough to cause periods of geomagnetic storming to the G1-G2 levels; although rarer cases of stronger storming may also occur. The larger and more expansive coronal holes can often be a source for high solar wind speeds that buffet Earth for many days.

NOAA informs that the solar activity is expected to be generally at very low levels till November 11. However, there is a chance for C-flares (relatively weak) with the return of old active regions (ARs) on the sun, designated 2682 and 2683. 

The agency expects one more G2-class storm on November 10 and forecasts a slight chance for R1-R2 (minor-moderate) radio blackouts between October 22 and October 24 due to the flare potential from AR 2685.

1 comment:

  1. G2-class storm can cause voltage alarms and transformer damage in high-latitude power systems

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