Solar activity remained high through February 2 as Region 4366 (beta-gamma-delta) continued to expand and develop a complex delta magnetic configuration.
This large region produced multiple M- and X-class flares over the past 36 hours, including an X8.1 flare at 23:57 UTC on February 1, an X2.8 at 00:36 UTC, and an X1.6 at 08:14 UTC on February 2.
The X8.1 event generated a CME observed departing the Sun’s northeastern quadrant in LASCO imagery at 00:12 UTC on February 2. Radio data from U.S. Air Force observatories recorded a Type II burst with a shock velocity of approximately 873 km/s (542 miles/s).
Modeling shows the eruption’s outer edge is likely to deliver a glancing impact to Earth’s magnetosphere late UTC on February 5, resulting in G1 – Minor geomagnetic storm conditions.
Possible effects under G1 conditions include weak power-grid fluctuations, minor spacecraft operations impacts, and auroral visibility across northern U.S. states such as Michigan and Maine.
Region 4366 remains the dominant source of solar activity on the visible disk, with continued growth in intermediary spots and increasing magnetic complexity. Two new regions, 4370 and 4371, rotated into view from the east limb but have not shown comparable activity.
SWPC forecasts moderate-to-high solar activity through February 5, with an 80% probability of M-class and a 40% probability of X-class flares from Region 4366.
Solar-wind measurements at L1 remained quiet on February 2, with total magnetic field (Bt) values between 4 and 7 nT, a southward Bz to –6 nT, and speeds near 300–315 km/s. A disturbance is expected on February 5 when the CME associated with the X8.1 flare arrives.
Electron flux levels exceeded 7 290 pfu at 20:30 UTC on February 2, while proton flux remained at background values. Minor S1 proton enhancements are possible between February 3 and 5 due to continuing activity from Region 4366 and associated ejecta.
Geomagnetic activity should remain quiet through February 4 before rising to storm levels as the CME arrives.
Forecast models show Planetary A index values rising to 16 on February 5 and mid-latitude K-indices up to 4, consistent with G1 conditions.
Region 4366 is one of the largest and most magnetically complex areas observed so far in Solar Cycle 25, which is currently approaching its maximum phase.
The X8.1 flare it produced on February 1 is the third-strongest flare of the cycle, following X9.0 on October 3, 2024, and X8.7 on May 14, 2024.
