Viewing archive of Sunday, 28 May 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 May 28 1458 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
28 May 2017	084	066
29 May 2017	085	015
30 May 2017	086	009

Bulletin

Over the past 24 hours solar activity has increased. There have been four B-flares flares originated at NOAA AR 2659 (McIntosh:Dai; Mag.Type:Beta). The biggest flare B9.2 peaked yesterday (27-Mar-2017) at 18:30 UT. No Earth-directed CMEs have been detected over the past 24 hours. Solar electron and proton fluxes have remained at background levels over the past 24 hours. NOAA AR 2659 is expected to produce more B-class and C-class flares over the next 24 hours.

Solar wind speed was fluctuating around 300 km/s (DSCOVR) until 14:50 UT yesterday when a small shock was observed in the solar wind due to the arrival of the 23-May-2017 coronal mass ejection. Initially, solar wind speed abruptly increased from 303 km/s to 385 km/s and density increased from 4.6 to 70p/cm3.

The Total Interplanetary Magnetic Field (IMF) strength Bt jumped from 2.5 to 10 nT, while the Bz component jumped to -8.5 nT. Later on yesterday, Bt reached a maximum of 22.30 nT at 22:30 UT and Bz component reached -20.5 nT value. Then Bt started to decrease gradually (till 16.5 nT), while Bz slowly returned to low values (-3.5 nT) being strongly negative. Solar wind speed is currently (28-May-2017 October, 12:30 UT) below 400 km/s.

Kp index reached moderate storm levels (Kp=6) from 21 UT (2017-05-27) to 03 UT (2017-05-28, today). During 03-06 UT, today Kp reached major storm levels (Kp=7) and during 06-12 UT again moderate and minor storm levels (Kp=6, Kp=5). Local K index at Dourbes was mostly at minor to major storming levels (K=5,4,5,6,7,5) from 21 UT (2017-05-27) to 12 UT (2017-05-28, today).

Total IMF strength is expected to remain at high levels tomorrow, and Bz component is not expected to become strongly negative. Solar Wind speed is expected to remain below 400 km/s. Therefore geomagnetic environment is expected to remain most probably at active conditions (Kp=4) for the next two days. However, isolated minor storming episodes (Kp=5) are still possible.

Today's estimated international sunspot number (ISN): 022, based on 26 stations.

Solar indices for 27 May 2017

Wolf number Catania	///
10cm solar flux	082
AK Chambon La Forêt	045
AK Wingst	013
Estimated Ap	017
Estimated international sunspot number	024 - Based on 31 stations

Noticeable events summary

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

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