Viewing archive of Saturday, 26 October 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Oct 26 1346 UTC

SIDC Forecast

Solar flares

Major flares expected (X-class flares expected, probability >=50%)

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

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

	10cm flux	Ap
26 Oct 2013	161	011
27 Oct 2013	161	014
28 Oct 2013	161	028

Bulletin

There were one X flare, six M flares, and thirteen C flares on the Sun in the past 24 hours. The X2.1 flare peaked at 15:03 UT on October 25 and was associated with a radio Type II burst with an estimated shock speed of 2078 km/s at Sagamore Hill. All M and X flares and five C flares were produced by beta-gamma-delta region NOAA AR 11882. Five C flares were released by beta-gamma-delta region AR 11875, and one C flare each by AR 11869, AR 11874 and beta-gamma region AR 11877. Type II bursts were also registered in association with the C2.3 flare released by AR 11875 peaking at 13:37 UT on October 25 (estimated shock speed 1083 km/s by Sagamore Hill) and the M1.5 flare released by AR 11882 peaking at 9:37 UT on October 26 (estimated shock speed 1275 km/s by San Vito). In the next 48 hours, X flares are possible, especially from NOAA AR 11882. There is a substantial risk of halo CMEs and the warning condition for proton storms remains valid. Several CMEs were ejected on October 25 and 26, among which two frontsided halo CMEs. The first halo CME was first observed by LASCO C2 at 8:24 UT on October 25 and was associated to the X1.7 flare. The second halo CME was first observed by LASCO C2 at 15:12 UT on October 25 and was associated with the X2.1 flare. Both CMEs are expected to arrive on October 28. Geomagnetic activity was at quiet levels (K Dourbes between 0 and 3; NOAA Kp between 0 and 2) during the past 24 hours. Active conditions (K Dourbes = 4) are expected for the second half of October 26, due to the expected arrival of the October 22 (M4.2) CME. Quiet conditions are expected on October 27, and minor storm conditions are expected on October 27 due to the expected merged arrival of several CMEs (among which the two halo CMEs of October 25).

Today's estimated international sunspot number (ISN): 085, based on 10 stations.

Solar indices for 25 Oct 2013

Wolf number Catania	142
10cm solar flux	161
AK Chambon La Forêt	007
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	096 - Based on 17 stations

Noticeable events summary

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

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