Viewing archive of Wednesday, 23 October 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Oct 23 1329 UTC

SIDC Forecast

Solar flares

Active (M-class flares expected, probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
23 Oct 2013	146	008
24 Oct 2013	146	013
25 Oct 2013	141	013

Bulletin

There were two M flares and seven C flares on the Sun during the past 24 hours. The brightest one was an M4.2 flare released by beta-gamma-delta region NOAA AR 11875 with peak time at 21:20 UT on October 22, and caused a Type II radio burst with estimated shock speed of 1955 km/s. All flares except a low C flare (from NOAA AR 11877) were produced by AR 11875. More M flares are likely from AR 11875 within the next 48 hours, with a slight chance for an X flare. In the past 24 hours, solar wind speed further increased from about 300 km/s to a maximum of about 400 km/s around 19h UT on October 22. It has since fluctuated between 340 and 400 km/s. In the same period, the Interplanetary Magnetic Field has varied between 4 and 9 nT, with current values around 5 nT. These variations are consistent with the influence of a weak coronal hole high speed stream. Solar wind speed is expected to return to nominal values on October 24. LASCO C2 observed a CME associated with a filament eruption at 4:36 UT on October 22, which has a slight chance of producing a glancing blow in the second half of October 24. Geomagnetic activity was at quiet levels (K Dourbes between 0 and 3; NOAA Kp between 1 and 2) during the past 24 hours. Quiet conditions (K Dourbes < 4) are expected for October 23 and the first half of October 24. Active conditions are possible in the second half of October 24 and on October 25, due to a possible glancing blow from the CME from October 22.

Today's estimated international sunspot number (ISN): 098, based on 12 stations.

Solar indices for 22 Oct 2013

Wolf number Catania	119
10cm solar flux	146
AK Chambon La Forêt	012
AK Wingst	005
Estimated Ap	005
Estimated international sunspot number	087 - Based on 23 stations

Noticeable events summary

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

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