Viewing archive of Tuesday, 21 July 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Jul 21 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
21 Jul 2015	091	016
22 Jul 2015	090	012
23 Jul 2015	090	016

Bulletin

The two currently visible sunspot groups are magnetically simple and quiet. No C-class flares or earth-directed coronal mass ejections (CMEs) were observed. Some filaments in particular near the east and southwest limb are present.

Quiet flaring conditions are expected, with a small chance on an isolated C-class flare.

Starting around 23:00UT, solar wind speed gradually increased from a steady 300 km/s to values fluctuating between 370 and 430 km/s between 05:00 and 09:00UT. Current speed varies between 360 and 400 km/s. Bz has been oscillating mostly between -8 and +10 nT since about midnight. These are likely the limited effects of the moderate speed stream from the positive trans-equatorial coronal hole (CH). So far, only unsettled geomagnetic conditions have been recorded. The interplanetary magnetic field (IMF) remained mostly directed away from the Sun. A positive CH between latitude 25 to 40 degrees north is transiting the central meridian and may affect the geomagnetic field starting 25 July.

Mostly quiet to unsettled geomagnetic conditions are expected, but with a chance on an active geomagnetic episode from the CH's wind stream on 21-22 July and the possible glancing blow from the 19 July CME late on 22 or on 23 July.

Today's estimated international sunspot number (ISN): 040, based on 21 stations.

Solar indices for 20 Jul 2015

Wolf number Catania	045
10cm solar flux	093
AK Chambon La Forêt	013
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	043 - Based on 24 stations

Noticeable events summary

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

All times in UTC

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