Viewing archive of Sunday, 24 April 2016

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2016 Apr 24 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
24 Apr 2016	081	010
25 Apr 2016	083	012
26 Apr 2016	085	007

Bulletin

Quiet solar weather conditions have been observed. The X-ray flux remained below C-level. Catania group 60 (NOAA regin 2533) remained a simple unipolar spot while renewed magnetic flux emergence and spot formation was observed in Catania group 59 (NOAA region 2532). A number of regions (though apparently rather inactive) or rotating onto the disk from the east while also some minor flux emergence and spot formation was noted near N07W60. Solar weather conditions are expected to be quiet with a small chance for C-flaring from the newly developing regions. A partial halo CME could be observed in SoHO/LASCO C2 coronagraph data from around 4:36 UT (April 24) onwards (It was wrongly classified as a Flow by CACTUS). The bulk of the mass is directed to the North and the angular extent was just below 180 degrees. From Stereo A EUVI 193 images the event can clearly be seen to originate from Catania group 54 (NOAA 2529) at the far side of the Sun. The CME will thus not impact Earth. No other CME's were detected in coronagraph data.

Solar wind conditions were back at nominal levels at the start of the period but started an unexpected renewed enhancement just after the start of the period. Solar wind speed increased steadily and constantly to present values of around 560 km/s with a peak of 600 km/s. The total field strength as measured by ACE saw a maximum of around 11nT around 18:30UT and afterwards decreased steadily to around 6nT presently. Bz was variable with southward deflections below -8nT in the UT afternoon of April 23. The magnetic field phi angle indicated a positive sector. Solar wind conditions are expected to recover to nominal over the next day but may remain enhanced initially. Geomagnetic conditions saw some active conditions to even minor storm levels around midnight associated to the southward Bz deflections (NOAA Kp 5 for one period, local K Dourbes 4). Otherwise quiet geomagnetic conditions were recorded. Given the present increased solar wind speed initially active geomagetic conditions remain possible over the next 24 hours should Bz turn pronounced negative. As speeds are afterwards expected to return to nominal, later quiet to unsettled conditions are expected.

Today's estimated international sunspot number (ISN): 038, based on 13 stations.

Solar indices for 23 Apr 2016

Wolf number Catania	///
10cm solar flux	079
AK Chambon La Forêt	022
AK Wingst	015
Estimated Ap	015
Estimated international sunspot number	016 - Based on 28 stations

Noticeable events summary

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

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