Solar alert

Issued on 2023 Jul 21 1247 UTC

A fast forward shock was observed in the solar wind parameters at 16:05 UTC on July 20th. The solar wind velocity increased from 366 km/s to 450 km/s. The interplanetary magnetic field jumped from 5 nT to 12 nT. The Bz reached a minimum of -10 nT. The solar wind density jumped from 2.6 ppc to 11 ppc and reached almost 18 ppc over the next hours. This caused active global (NOAA KP = 4) conditions and a minor storm period occurring locally (K-Bel = 5). This may mark the expected arrival from the partial halo CME from July 17. The current solar wind speed is close to 400 km/s with magnetic field values around 5 nT. The orientation of the interplanetary magnetic field has mainly stayed in the negative sector (directed towards the Sun). Enhanced solar wind conditions are expected on July 21 and 22, from the expected ICME arrival and possibly weak High Speed Stream (HSS) effects.

Reference for this alert

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