CME headed toward Earth, impact expected around 12:00 UTC on May 26


An eruption near the center of Earth-facing side of the Sun produced a partial HALO CME (coronal mass ejection) during the early UTC hours of May 23, 2017. The CME is weak, but it has an Earth-directed component.

Arrival at Earth is expected around 12:00 UTC on May 26. Unsettled to active geomagnetic field conditions are expected, with a slight chance for G1 – Minor geomagnetic storm.

YouTube video

Earth-directed CME - May 23, 2017

Image courtesy NASA/SDO. Annotation Dr. Tamitha Skov

Solar activity was very low during the past 24 hours and is expected to remain very low, with a slight chance for C-class flares, through May 26. Region 2659 (N13W12, Cro/beta) grew in spot count and is now the only spotted region on the disk.

Sunspots on May 24, 2017

Sunspots on May 24, 2017. Credit: NASA/SDO HMI

The greater than 2 MeV electron flux reached high levels over the past 24 hours with a peak flux of 9,333 pfu observed at 14:30 UTC on May 23. The greater than 10 MeV proton flux remained at background values.

The greater than 2 MeV electron flux is expected to reach high levels, with a chance for very high levels, on May 24 and 25 in response to elevated wind speeds from CH HSS influence.

By May 26, the arrival of the May 23rd CME is likely to cause a redistribution of particles, returning flux levels to near background conditions. The greater than 10 MeV proton flux is expected to continue at background levels.

Solar wind parameters were indicative of persistent, but waning CH HSS influence over the past 24 hours. They are expected to remain slightly enhanced, yet continue to slowly diminish through May 25 as CH HSS influences continue to wane.

Mid to late May 26, solar wind parameters are expected to become enhanced and disturbed with the arrival of the May 23rd CME.

Featured image credit: NOAA/SWPC WSA-Enlil


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  1. doesn’t anyone worry that this event will hit the east coast of the united states on the Friday of Memorial day weekend at 7am eastern time ? this could result in a traffic snafu
    of epic proportions.

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