Solar flux 178 and estimated planetary A-index 143. The estimated planetary K-index at 1800 UTC on 21 January was 4.00. Space weather for the past 24 hours has been severe. Geomagnetic storms reaching the G4 level occurred. Solar radiation storms reaching the S1 level occurred. Radio blackouts reaching the R1 level occurred.

Forecast Issued at 2200Z on 20 Jan 2026

Solar Activity Forecast: Solar activity is likely to be moderate with a slight chance for an X-class flare on days one, two, and three (21 Jan, 22 Jan, 23 Jan).

Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to severe storm levels on day one (21 Jan), unsettled to active levels on day two (22 Jan) and quiet to unsettled levels on day three (23 Jan). Protons are expected to cross threshold on day one (21 Jan), have a chance of crossing threshold on day two (22 Jan) and have a slight chance of crossing threshold on day three (23 Jan).