Viewing archive of Friday, 17 April 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Apr 17 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
17 Apr 2015	158	024
18 Apr 2015	163	012
19 Apr 2015	168	008

Bulletin

Out of several low C-class flares reported during last 24 hours, the strongest one was the C3.3 flare which peaked at 19:18 UT on April 16. The flare originated from the Catania sunspot group 33 (NOAA AR 2325). We expect C-class flares and probably also an isolated M-class flare, in particular from the NOAA AR 2321 and 2324 which currently have beta-gamma configuration of the photospheric magnetic field. No Earth directed CMEs were observed during last 24 hours. The Earth is still inside a fast flow with the speed of 660 km/s. The interplanetary magnetic field magnitude has decreased to about 5nT, and the Bz component of the interplanetary magnetic field is presently positive (about 1nT). If the Bz component will turn to negative values it might induce the geomagnetic storm conditions. In the late evening of April 16 and early morning of April 17, the solar wind speed reached the value of 780 km/s. Concurrently with the increase of the solar wind speed, the Bz component of the interplanetary magnetic field had few intervals of negative value (mostly about -7nT, with minimum reported value of about -12nT). These conditions induced the geomagnetic storm, NOAA reported Kp=6 and local stations at Dourbes and IZMIRAN reported K=5 and K=6, respectively. The geomagnetic conditions are presently active, and we expect active to possibly minor storm geomagnetic conditions in the coming hours.

Today's estimated international sunspot number (ISN): 085, based on 09 stations.

Solar indices for 16 Apr 2015

Wolf number Catania	163
10cm solar flux	150
AK Chambon La Forêt	055
AK Wingst	037
Estimated Ap	041
Estimated international sunspot number	075 - Based on 29 stations

Noticeable events summary

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

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