Viewing archive of Thursday, 31 December 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Dec 31 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

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

	10cm flux	Ap
31 Dec 2015	100	049
01 Jan 2016	102	031
02 Jan 2016	105	024

Bulletin

Solar activity was low. The only prominent region on disk, NOAA 2473, showed decay and produced the only 2 C flares of the period of which the strongest a C4.3 flare peaking at 22:45UT. NOAA AR 2473 continued to show decay, especially in the trailing spots. Flaring at C level is expected with only a slight chance for an M flare from NOAA AR 2473. No Earth directed CMEs have been recorded. The >10MeV have recovered to nominal values with a slight chance for a proton event remaining, associated with possible activity from region 2473. Solar wind conditions remained nominal until midnight when at 00:02UT a shock occurred in ACE solar wind data, marking the arrival of the December 28 CME. Total interplanetary magnetic field jumped from 6nT to 13nT while solar wind speed jumped from 340km/s to 400 km/s. Solar wind speed kept increasing to a peak of around 500 km/s and is currently at around 460 km/s. Total magnetic field was in the 9-16nT range but Bz was initially variable and remained above -10nT. More recently, stronger and more pronounced negative peaks down to -13nT are recorded. Solar wind conditions are expected to remain enhanced over the next days in the wake of the CME today and into a sector boundary crossing with later the possible high speed stream influence from the low latitude extension of the (positive polarity) northern polar coronal hole. Only up to active geomagnetic conditions have been reported so far (both NOAA Kp and local K Dourbes reached 4). Subject to the evolution of the magnetic field and its Bz component minor to major geomagnetic storming conditions remain possible in the wake of the CME later easing to possible isolated active periods.

Today's estimated international sunspot number (ISN): 019, based on 17 stations.

Solar indices for 30 Dec 2015

Wolf number Catania	///
10cm solar flux	102
AK Chambon La Forêt	012
AK Wingst	004
Estimated Ap	003
Estimated international sunspot number	030 - Based on 30 stations

Noticeable events summary

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

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