Viewing archive of Tuesday, 19 December 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Dec 19 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
19 Dec 2017	071	001
20 Dec 2017	071	017
21 Dec 2017	072	015

Bulletin

Very quiet Solar conditions were reported. A small unipolar sunspot (numbered Catania group 67) has rotated on disk in the North-East and seems to be in a growing phase. It is the only region on disk. X-ray flux is expected to remain below C level. No earth directed CMEs have been observed in coronagraph data. Solar Proton flux levels are at background values and are expected to remain so.

The declining phase of the current high speed stream set in late in the afternoon December 18 with speeds declining from around 640 km/s to just over 500 km/s now. Total magnetic field was between 3 and 8nT with Bz mostly positive. Solar wind speed is expected to further decline over the next 24 hours. A disturbance of the Solar wind conditions could occur tomorrow before noon due to the possible influence of the December 15 CME. Later there may be a minor influence of the elongated equatorial coronal hole that started transiting the central meridian yesterday. However, the coronal hole seems to be breaking up and it is uncertain whether the leading portion will have any effect at Earth. Geomagnetic conditions were quiet to unsettled (both local K Dourbes and NOAA Kp 1-3) and are expected to remain so. An active period related to the possible CME arrival can however not be excluded.

Today's estimated international sunspot number (ISN): 007, based on 16 stations.

Solar indices for 18 Dec 2017

Wolf number Catania	000
10cm solar flux	072
AK Chambon La Forêt	016
AK Wingst	016
Estimated Ap	017
Estimated international sunspot number	000 - Based on 21 stations

Noticeable events summary

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

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