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G4 (Severe) Watch in Effect for 12 November(swpc.noaa.gov)
19 points by hnburnsy a day ago | 5 comments
  • h2zizzlea day ago

    >To include

    "Including", or "which is to include/which may include".

  • superkuha day ago

    But we won't actually know anything till about 1 hour before it happens. That's when any potential interplanetary coronal mass ejections actually have their magnetic field orientation and intensity measured by ACE and other satellites far out at the L1 lagrange point: https://services.swpc.noaa.gov/images/ace-mag-swepam-24-hour...

    If you see the red line on this plot, the interplanetary magnetic field, be more than -10 nanotesla for about 4 hours then there's a good chance of lower than normal latitude aurora. Negative means the magnetic field is pointing downwards out of the ecliptic plane of the solar system and this is the most energetically favorable orientation for reconnecting CME magnetic field lines with Earth's magnetic field lines and letting solar particles/energy in.

    It can be 20nT positive (upwards) magnetic field with intense density and high velocity but still be a non-event aurora-wise just because energy is delivered to the Earth's ring currents at 10x slower rate than if it's pointing downwards.

    None of the WSA-ENLIL or related predictive models take into consideration the magnetic field orientation of iCMEs because it's really hard to know from remote observations. They can be thought of as warnings to pay attention to the ACE L1 measurements.

    • inhumantsara day ago |parent

      does that apply to the OVATION model used in NOAA's aurora forecast? https://www.swpc.noaa.gov/communities/aurora-dashboard-exper...

  • brador19 hours ago

    11 Nov G2 (Moderate); 12 Nov G4 (Severe); and 13 Nov G3 (Strong).

  • vorpalhexa day ago

    We had a G5 in 2024 and I believe the only possibly related issue was some cellular infrastructure in Europe (local impact only).

    Modern technology is significantly more hardened than telegraphs in the 1800s.