Viewing archive of Friday, 28 December 2018

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2018 Dec 28 1230 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
28 Dec 2018	069	016
29 Dec 2018	069	015
30 Dec 2018	069	010

Bulletin

Solar activity was at very low levels. The solar disk remained free of sunspots. No coronal mass ejections (CMEs) were observed over the last 24 hours. The greater than 10 MeV proton flux was at nominal values.

Solar activity is expected to remain at very low levels.

The co-rotating Interaction Region (CIR) and High Speed Stream (HSS) associated with the positive polarity coronal hole (CH) arrived earlier than expected. The CIR passed L1 (1st Lagrange point) around 19UT on 27 December, with Bz varying between -11 and +10 nT for the remainder of the period (DSCOVR). Solar wind speed gradually increased from values around 330 km/s to a maximum near 610 km/s at 10UT. The direction of the interplanetary magnetic field switched from towards the Sun to away from the Sun around 22UT. Kp was at active to minor storming levels (Kp = 4 to 5), whereas the local K index at Dourbes only reached unsettled conditions (K = 3). The Dst index reached a modest -8 nT at 03UT.

Quiet to active geomagnetic conditions are expected for the next two days as Earth remains under the influence of the CH HSS. A minor storming interval is not excluded. Geomagnetic conditions are expected to return to mostly quiet to unsettled levels from 30 December onwards.

Today's estimated international sunspot number (ISN): 000, based on 10 stations.

Solar indices for 27 Dec 2018

Wolf number Catania	000
10cm solar flux	069
AK Chambon La Forêt	018
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	000 - Based on 24 stations

Noticeable events summary

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

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