Viewing archive of Thursday, 25 March 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Mar 25 1230 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
25 Mar 2021	080	021
26 Mar 2021	079	010
27 Mar 2021	078	026

Bulletin

Solar activity was at very low levels in the past 24 hours. NOAA AR 2811 and 2812 produced only B-class flares. Solar activity is expected to remain at low levels.

No Earth directed CMEs were observed in the past 24 hours.

An equatorial negative polarity coronal hole crossed the central meridian yesterday, its associated high speed stream will arrive at the Earth in about 48 hours.

The greater than 10 MeV proton flux was below nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux was above the 1000 pfu threshold on 24 March, and below it on 25 March, it is expected to remain low in the next 24 hours. The 24h electron fluence was at moderate levels in the last 24 hours and is expected to go to normal levels in the next 24 hours.

The solar wind speed varied between 380 km/s to 450 km/s. The interplanetary magnetic field magnitude varied between 1 and 8 nT. Bz was between 4 and -7 nT. The magnetic field phi angle had mostly positive polarity (away form the Sun). There are signs of an ICME in the solar wind starting around 19:00 UT, corresponding to the expected arrival of the CME from 20 March. This was marked mostly by a sudden increase in solar wind speed and magnetic field and followed by several hours of negative Bz. Slow solar wind conditions are expected in the next 24 hours.

Geomagnetic conditions reached minor storm levels at planetary levels (Kp = 5) and active levels locally (KDourbes = 4), due to the ICME arrival. The CME observed on 22 March is expected to arrive to the Earth on March 26-27, it is expected to cause at most active conditions (otherwise mostly quiet conditions expected).

Today's estimated international sunspot number (ISN): 024, based on 16 stations.

Solar indices for 24 Mar 2021

Wolf number Catania	030
10cm solar flux	084
AK Chambon La Forêt	027
AK Wingst	013
Estimated Ap	012
Estimated international sunspot number	027 - Based on 23 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

All times in UTC

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