Viewing archive of Wednesday, 20 December 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Dec 20 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
20 Dec 2017	070	008
21 Dec 2017	071	016
22 Dec 2017	071	007

Bulletin

Solar activity was very low with only a couple of low level B class flares from the only region on disk Catania sunspotgroup 67. The region is still fairly simple but has shown quite some growth this morning. Flaring is expected to remain below C level. A filament eruption is seen off the North Eastern hemisphere around 3:00UT. Coronagraph data are not yet available to assess the extent of the likely associated CME. Proton flux values are at background levels and expected to remain so.

Solar wind has recovered to background conditions with Solar wind speed dropping to 450 km/s by around 2:00 UT this morning and remained stable since. Total magnetic field has been fluctuating around 3-4nT with a variable Bz. A possible arrival of the December 15 CME is no longer expected. A transition into a negative sector is expected within the next 24 hours with then also the influence of the negative polarity equatorial coronal hole possibly setting in. However, the leading part of the coronal hole which passed the central meridian on December 18 is not likely to bring any strong effects. A more significant high speed stream influence is only expected 3-4 days from now from the trailing part of the coronal hole which only now starts passing the central meridian. Geomagnetic conditions were quiet to unsettled (both local K Dourbes and NOAA Kp 1-3). Quiet to unsettled conditions are expected over the next days.

Today's estimated international sunspot number (ISN): 011, based on 06 stations.

Solar indices for 19 Dec 2017

Wolf number Catania	011
10cm solar flux	069
AK Chambon La Forêt	012
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	007 - Based on 19 stations

Noticeable events summary

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

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