Solar alert

Issued on 2023 Apr 23 1833 UTC

A fast forward shock was observed in the solar wind at 17:00 UTC on April 23rd marking the expected arrival of a fast CME, which lifted off the solar surface on April 21st as a result of long duration M-class flaring triggered by a neighbouring filament eruption. The interplanetary magnetic field jumped from 9 nT to 26 nT with Bz reaching -24 nT. The solar wind velocity increased from 360 km/s to 480 km/s and the density jumped from 4.8 ppcc to 16.8 ppcc. The solar wind speed around 17:45 UTC has reached 527 km/s. The current geomagnetic conditions are active over Belgium and globally at minor storm levels. Moderate to major storms are expected in the upcoming hours with the ongoing ICME arrival. The greater than 10 MeV GOES proton flux has reached minor radiation storm levels and is expected to continue to increase, possibly reaching moderate radiation storm levels.

Issued on 2023 Apr 23 2026 UTC

A major geomagnetic storm has been registered over Belgium due to an ongoing ICME arrival. The solar wind velocity has exceeded 610 km/s with interplanetary magnetic field values of 27 nT and a minimum BZ component of -25 nT. The solar wind density has exceeded 32 ppcc and the temperature is above 1 MK. The geomagnetic conditions are expected to remain at moderate to major storm levels in the upcoming hours. The greater than 10 MeV GOES proton flux remains enhances, but has decreased to below minor storm radiation levels. Related to the storm there are ongoing strong ionospheric scintillations and post storm depressions, as well as some polar cap and auroral absorptions.

Reference for this alert

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