Viewing archive of Monday, 20 February 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Feb 20 1238 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
20 Feb 2017	080	014
21 Feb 2017	082	017
22 Feb 2017	084	021

Bulletin

Solar activity was dominated by the sunspot groups rotating onto the disk in the NE. The Sunspot groups are numbered Catania 95 and 96 (together NOAA 2638). They produced the largest flare of the period: a B4.5 flare peaking at 11:29UT. An additional more simple region in the South- East got numbered Catania 94 (NOAA 2637). Chances for C flares have increased but are still not very probable. The equatorial part of the positive polarity coronal hole in the Southern hemisphere is transiting the central meridian today and is expected to enhance solar wind conditions again by February 23. Some faint North-Eastward CME seems to be associated with the filament eruption of February 19, but it's possible influence on Earth is not expected to be distinguishable in the high speed stream effects expected on February 23. No other Earth directed CMEs have been observed in coronagraph data. Proton flux is at background values and expected to remain so.

Solar wind speed has been declining from over 550 km/s to around 500 km/s while the total magnetic field around a nominal 5nT and Bz was mostly variable. Solar wind conditions are initially expected to further decline but should see an increase again by February 23 as the equatorial part of the positive polarity coronal hole becomes geoeffective. Geomagnetic conditions were quiet to unsettled (local K Dourbes 0-3 and NOAA Kp 1-3) and are expected to remain so over the next days before a renewed period of active to minor storm levels is expected under the influence of the equatorial part of the coronal hole.

Today's estimated international sunspot number (ISN): 034, based on 14 stations.

Solar indices for 19 Feb 2017

Wolf number Catania	///
10cm solar flux	078
AK Chambon La Forêt	015
AK Wingst	014
Estimated Ap	012
Estimated international sunspot number	022 - Based on 22 stations

Noticeable events summary

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

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