Viewing archive of Monday, 18 December 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Dec 18 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
18 Dec 2017	070	026
19 Dec 2017	070	022
20 Dec 2017	070	019

Bulletin

The Sun is spotless and no significant flaring activity was recorded. No flaring activity is expected over the next 24 hours. There were no CMEs observed in coronagraph data. The proton flux values are at background levels and are expected to remain so. An elongated negative polarity equatorial coronal hole started transiting the central meridian. It may influence solar wind from November 20 onwards.

Solar wind is under the expected influence of a positive polarity coronal hole high speed stream. Since just after the start of the reporting period solar wind speed has been between 575 and 650 km/s. Total magnetic field was between 5-10nT with negative peaks of Bz down to -7nT. Based on Stereo A Solar wind measurements, the influence of the high speed stream is expected to decay over the next 24 hours. On December 20 we may see some minor influence of the December 15 CME and later on a renewed increase in Solar wind conditions due to the negative polarity equatorial coronal hole currently transiting the central meridian.

Geomagnetic conditions have seen a minor storm period in the afternoon of December 17 with both NOAA Kp and local K Dourbes reaching K=5. Afterwards, quiet to active conditions were reported (NOAA Kp 3-4 and local K Dourbes 2-4). With Solar wind speed still high, periods of active geomagnetic conditions should be anticipated but should become less likely over the next 24-48 hours. Renewed increases of geomagnetic activity may follow starting December 20 caused by the possible December 15 CME influence and later increased Solar wind conditions due to the negative polarity equatorial coronal hole currently transiting the central meridian.

Today's estimated international sunspot number (ISN): 000, based on 14 stations.

Solar indices for 17 Dec 2017

Wolf number Catania	///
10cm solar flux	071
AK Chambon La Forêt	044
AK Wingst	026
Estimated Ap	028
Estimated international sunspot number	000 - Based on 19 stations

Noticeable events summary

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

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