Viewing archive of Wednesday, 17 December 2014

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2014 Dec 17 1232 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

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

	10cm flux	Ap
17 Dec 2014	185	008
18 Dec 2014	185	007
19 Dec 2014	180	010

Bulletin

The Sun released three M flares and four C flares during the past 24 hours. An M8.7 flare was released by NOAA AR 2242 on December 17 with peak time 04:51 UT. It was preceded by an M1.5 flare produced by AR 2242 peaking at 1:10 UT and an M1.1 flare produced by AR 2241 peaking at 1:50 UT. An associated Type II radio burst was observed by Learmonth observatory between 4:49 and 5:15 UT with an estimated speed of 910 km/s. After a data gap, LASCO C3 imagery showed a CME first detected at 9:18 UT on November 17 and probably associated to the M8.7 flare. Since AR 2242 is close to the central meridian, this CME is expected to become geoeffective. Using a speed of 910 km/s as estimated by the Type II radio burst, a tentative arrival time around UT midnight on December 19-20 is obtained. M and even X flaring from AR 2242 and AR 2241 are possible in the next 24 hours. There is a chance for proton storms in the days ahead. In the past 24 hours, solar wind speed observed by ACE fluctuated between about 370 and 470 km/s. The magnitude of the Interplanetary Magnetic Field (IMF) was stable and mainly between 5 and 6 nT. Over the past 24 hours, geomagnetic conditions were quiet (K Dourbes between 1 and 3; NOAA Kp between 2 and 3). Quiet geomagnetic levels (K Dourbes < 4) are expected on December 17, 18 and the first half of December 19. Active to minor storm conditions are possible in the second half of December 19 in view of the expected CME arrival.

Today's estimated international sunspot number (ISN): 137, based on 07 stations.

Solar indices for 16 Dec 2014

Wolf number Catania	///
10cm solar flux	185
AK Chambon La Forêt	016
AK Wingst	008
Estimated Ap	008
Estimated international sunspot number	124 - Based on 18 stations

Noticeable events summary

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

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