Viewing archive of Saturday, 23 July 2016

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2016 Jul 23 1230 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
23 Jul 2016	093	008
24 Jul 2016	090	006
25 Jul 2016	087	016

Bulletin

NOAA 2567 started another active flaring episode shortly after midnight producing 3 M-class flares. The intensities and peak timings of the events were resp. M5.0 (02:11UT), M7.6 (05:16UT), and M5.5 (05:31UT). In particular the last event was accompanied by an impressive ejection of material. San Vito reported a type II radio burst with related shock speed of the disturbance of 729 km/s. The greater than 10 MeV proton flux is somewhat enhanced (0.77 pfu at 07:25UT), but has remained so far well below the event threshold (10 pfu). The currently available coronagraphic images show that the bulk of the associated coronal mass ejections (CMEs) is directed away from the Earth. However, a glancing blow from the CME of the double-peaked M-class event cannot be excluded. No other earth-directed CMEs were observed.

An accurate assessment of the magnetic configuration of the NOAA 2565 / 2567 sunspot cluster is difficult due to its close proximity near the west limb. Nonetheless, further M-class flaring is possible, with a small chance on an X-class flare. A warning for a potential proton event has been put into effect.

The interplanetary magnetic field was directed towards the Sun (negative), except during the 17:00-02:00UT interval when it was steadily positive (away from the Sun). This interval corresponded to somewhat elevated solar wind speeds between about 440 and 500 km/s and Bz near 0 nT. At the end of the reporting period, solar wind parameters were back at nominal values with wind speed near 390 km/s, and Bz varying between -8 and +7 nT. A small positive coronal hole (CH; latitude +20 degrees) is near the central meridian. Quiet to unsettled geomagnetic conditions were observed.

Mostly quiet to unsettled geomagnetic conditions are expected. An active episode is not excluded, in particular on 25 July when a glancing blow from the 23 July CME is possible.

Today's estimated international sunspot number (ISN): 030, based on 22 stations.

Solar indices for 22 Jul 2016

Wolf number Catania	057
10cm solar flux	090
AK Chambon La Forêt	018
AK Wingst	012
Estimated Ap	011
Estimated international sunspot number	044 - Based on 30 stations

Noticeable events summary

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

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