Viewing archive of Saturday, 11 April 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Apr 11 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
11 Apr 2015	120	020
12 Apr 2015	123	007
13 Apr 2015	126	007

Bulletin

Beta-delta region NOAA AR 2320 released two C flares and a new region on the East limb each released one C flare during the past 24 hours. The strongest flare was the C4.7 flare produced by the new region, which peaked at 2:41 UT on April 11. In the next 24 hours, more C flaring is expected, with a chance for an M flare. During the past 24 hours, solar wind speed decreased from about 410 km/s to 360 km/s while the Interplanetary Magnetic Field (IMF) magnitude decreased from about 20 to 5 nT. Bz reached -12 nT at short intervals and stayed below -5 nT from about 13:15 to 8:15 UT. The Phi angle switched from a positive (away) towards a negative (towards) sector in the first half of April 11. Over the past 24 hours, geomagnetic conditions have been quiet to active (K Dourbes between 2 and 4; NOAA Kp between 2 and 4) as a response to the elevated solar wind speed and IMF magnitude. Quiet to active geomagnetic levels are expected to continue for the rest of April 11, while quiet levels (K Dourbes < 4) are predicted for April 12 and 13.

Today's estimated international sunspot number (ISN): 031, based on 15 stations.

Solar indices for 10 Apr 2015

Wolf number Catania	071
10cm solar flux	115
AK Chambon La Forêt	034
AK Wingst	031
Estimated Ap	030
Estimated international sunspot number	031 - Based on 28 stations

Noticeable events summary

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

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