Geomagnetic Activity Report for September 16, 2024
Geomagnetic storms occur due to large disturbances in Earth’s magnetic field. These disturbances arise from solar wind patterns and interplanetary magnetic field (IMF) changes. Such changes stem from solar events, notably powerful coronal mass ejections (CMEs). The effects of these storms can persist for several days. When conditions align, high solar wind speed and density can transfer significant energy into Earth's geomagnetic system.
The consequences of geomagnetic storms can include impacts on power systems, communications, and spacecraft operations.
Today's solar activity (16 September) is K-INDEX 7 (high).
Forecast Overview
Space Weather Forecast Headline: Moderate class flares are likely, with a slight chance for stronger flares. Instances of G1-G2 (Minor-Moderate) storms are expected on days 1 and 3 (15 and 17 Sep), with risks peaking on day 2 (16 Sep). On this day, G3/Strong storm conditions could arise due to the whiplash effect from fast CMEs.
Analysis of Space Weather Activity
Past 24 Hours Solar Activity: High. The peak flare occurred on 14 September at 14:28 UTC, driven by AR2825 located in the southeast.
Currently, there are seven notable sunspot regions, the most active being AR3825. This region holds a compact structure with a strong magnetic imbalance. The other areas display limited activity and magnetic complexity.
Multiple CMEs were observed; one near the southwest limb was detected around 14 September at 03:00 UTC. This CME is under observation for any Earth-directed components, while many others do not appear to have Earth-directed pathways.
Solar Wind / Geomagnetic Activity: Measures indicate residual effects from coronal mass ejection activity. Slightly elevated solar wind speeds were noted. The Interplanetary Magnetic Field (IMF) exhibited weak to moderate intensity. The north-south component of Bz remained mostly negative, yielding unsettled to active geomagnetic conditions (Kp values of 3-4).
Energetic Particles / Solar Radiation: There has been a steady rise in high-energy protons since the strong flare on 14 September, stabilizing at moderate levels.
Four-Day Space Weather Forecast Summary
Solar Activity: Moderate to high levels are anticipated, with M-class flares expected and a slight chance of X-class flares, primarily from the southeast sunspot group.
Solar Wind / Geomagnetic Activity: The forecast mentions the arrival of up to 3 CMEs, as well as winds from three coronal holes. The notable feature is the CME from 14 September, which may result in strong solar winds at Earth on day 2 (16 Sep). This a possibility that could happen sooner, by late day 1 (15 Sep), and may extend effects into day 3 (17 Sep) combined with another wind system. On day 4, additional winds could yield elevated speeds.
Geomagnetic activity will likely range from generally quiet to active on day 1 (15 Sep), with minimal risks for G1-G2 storms. Should the 14 September CME arrive earlier and with more intensity than anticipated, this risk could manifest as G3-5 (Strong-Extreme) storms. The CME will likely have glancing impacts around day 2, forecasting G1-G2 storms and a chance of G3 conditions, while risks will taper off by days 3 and 4 (17 and 18 Sep) due to diminishing CME effects.
Energetic Particles / Solar Radiation: The count rate of high-energy protons could rise further following the X4.5 flare, possibly challenging the S1 Minor Radiation Storm threshold on 14 September. However, this risk diminishes later in the forecast period.
