Viewing archive of Thursday, 16 April 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Apr 16 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
16 Apr 2015	158	020
17 Apr 2015	163	008
18 Apr 2015	167	006

Bulletin

The strongest flare reported during last 24 hours was the C7.8 flare, peaking at 20:23 UT on April 15. The flare originated from, still the most complex region visible on the solar disc, NOAA AR 2321 (altogether Catania sunspot groups 29, 30 and 31). We expect C-class flares and possibly also an isolated M-class flare, in particular from NOAA ARs 2321, 2324, and 2325. No Earth directed CMEs were observed during last 24 hours. The Earth is inside the fast solar wind with the speed of about 620 km/s. The interplanetary magnetic field magnitude has decreased and its present value is about 7nT. During the last 24 hours the Bz component of the interplanetary magnetic field had a few longer intervals of negative value (mostly about - 6 nT, with minimum reported value of about -12nT) which induced minor storm geomagnetic conditions (local station at Dourbes and IZMIRAN reported K=5; NOAA reported Kp= 5). CME of April 12 might arrive at the Earth today. We expect active to possibly minor storm geomagnetic conditions in the coming hours.

Today's estimated international sunspot number (ISN): 083, based on 17 stations.

Solar indices for 15 Apr 2015

Wolf number Catania	125
10cm solar flux	155
AK Chambon La Forêt	038
AK Wingst	033
Estimated Ap	030
Estimated international sunspot number	073 - Based on 25 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page