Viewing archive of Tuesday, 30 May 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 May 30 1247 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
30 May 2017	073	008
31 May 2017	071	007
01 Jun 2017	069	024

Bulletin

Solar activity was low with the strongest flare a B6.8 flare peaking at 14:48UT from the only region on disk NOAA 2659. The region has meanwhile rotated behind the West limb. Solar X-ray flux is expected to remain at background level. No Earth directed CMEs have been observed in coronagraph data. SDO/AIA 304 images showed the start of the eruption of the 35 degree long filament located in the South-Eastern hemisphere, just at the end of the reporting period. We will report on a possible related CME when further data becomes available. Proton flux levels were at background values and are expected to remain so. A small positive polarity equatorial coronal hole crossed the central meridian overnight, and may influence Earth from June 1 onwards.

Solar wind saw the return to nominal solar wind conditions after the May 23 CME passage, with afterwards a somewhat unexpected increase in solar wind speed late in the period. After a short initial period of negative Bz (down to -15nT), total magnetic field dropped around 15:00UT to nominal levels near 5nT and remained in the 4-9nT for the remainder of the period wit Bz variable. Solar wind speed has been increasing since and currently reaches elevated values of 530 km/s. These could be associated with a rather vaguely defined equatorial coronal hole passing the central meridian late May 27. Slightly elevated wind speeds are expected to persist over the next day, with from June 1 onwards a possible further increase due to the coronal hole that crossed the central meridian last night. Geomagnetic conditions reached active levels (NOAA Kp and local K Dourbes 4) associated with the negative Bz at the start of the period but were otherwise quiet to unsettled. Quiet to unsettled geomagnetic conditions are expected over next days with later active periods possible form June 1 onwards.

Today's estimated international sunspot number (ISN): 000, based on 16 stations.

Solar indices for 29 May 2017

Wolf number Catania	015
10cm solar flux	076
AK Chambon La Forêt	021
AK Wingst	011
Estimated Ap	011
Estimated international sunspot number	014 - Based on 34 stations

Noticeable events summary

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

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