Viewing archive of Monday, 13 April 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Apr 13 1232 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

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

	10cm flux	Ap
13 Apr 2015	138	011
14 Apr 2015	145	014
15 Apr 2015	148	017

Bulletin

The strongest flare reported during the last 24 hours was the C9.0 flare which peaked at 18:07 UT on April 12. The flare originated from the NOAA AR 2321, situated at that moment close to the east solar limb. No clear signatures of the CME possibly associated with this flare are visible in the currently available data. The NOAA AR 2321 presently has beta-gamma- delta configuration of its photospheric magnetic field and therefore also potential to be the source of C-class and M-class flares in the course of coming hours. The partial halo CME, first seen in the SOHO LASCO C2 field of view at about 23:36 UT on April 12 was associated with the flare and the filament eruption triggered by the flare (from the close to the west solar limb region). The associated type II radio burst, signature of the shock wave, was reported by Culgoora Observatory. The radio burst gives indication that the speed of the associated shock was about 1100 km/s. The CME had the angular width of about 150 degrees and the projected plane of the sky speed of about 630 km/s. The expected CME arrival at the Earth is in late evening of the April 15 or early morning of April 16. The Earth is still inside a slow solar wind with the speed of 350 km/s, and the interplanetary magnetic field is currently rather low with the magnitude of about 2nT. The geomagnetic conditions are currently quiet, and we expect quiet to unsettled geomagnetic conditions in the coming hours. The arrival of the fast flow, from the southern polar coronal hole which has strong extend towards the solar equator, is expected in the afternoon of April 14 and morning of April 15 with possible active geomagnetic conditions.

Today's estimated international sunspot number (ISN): 077, based on 18 stations.

Solar indices for 12 Apr 2015

Wolf number Catania	///
10cm solar flux	134
AK Chambon La Forêt	010
AK Wingst	005
Estimated Ap	004
Estimated international sunspot number	064 - Based on 26 stations

Noticeable events summary

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

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