Viewing archive of Saturday, 22 April 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Apr 22 1230 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
22 Apr 2017	082	047
23 Apr 2017	083	022
24 Apr 2017	084	007

Bulletin

Three ARs on the visible disk (NOAA AR 2653 rotated into view today), all with simple magnetic field configuration. No C-class flares in past 24 h, although they are likely to happen in the next 24 h.

No Earth directed Coronal Mass Ejections (CMEs) have been detected. Solar protons have remained at background levels over the past 24 hours.

The Earth left the influence of the positive polarity equatorial hole yesterday in the morning. Soon after (around 12:00 UT) the interplanetary magnetic field and solar wind speed increased, while the solar wind temperature went down, marking the presence of an ICME. This was most likely a glancing blow from the CME on April 18. In the evening, the solar wind showed signatures of a high speed stream, the speed increased to ~800 km/s currently with interplanetary magnetic fields of 10 nT. This caused minor storm conditions locally and major storm at planetary levels. This high speed stream comes from the equatorial extension of the southern coronal hole (negative polarity), and its arrival comes more than 1 day earlier than expected (that is due to the very high speeds of its solar wind). Geomagnetic conditions are expected to reach major storm levels with isolated severe storm periods.

Today's estimated international sunspot number (ISN): 030, based on 15 stations.

Solar indices for 21 Apr 2017

Wolf number Catania	///
10cm solar flux	082
AK Chambon La Forêt	039
AK Wingst	024
Estimated Ap	022
Estimated international sunspot number	040 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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