Viewing archive of Monday, 27 May 2019

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2019 May 27 1230 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
27 May 2019	068	011
28 May 2019	068	018
29 May 2019	069	012

Bulletin

The solar activity has been quiet over the past 24 hours. The X-ray flux remains below B-level and the visible solar disc is spotless. Solar activity is expected to remain at low levels very low over the next 24 hours.

No Earth directed Coronal Mass Ejection (CME) has been detected in the available coronagraph imagery. The greater than 10 MeV solar protons flux remained at nominal levels over the past 24 hours and is expected to remain so.

At the beginning of the period, the solar wind parameters were at nominal levels: the wind speed was slower than 350 km/s, the interplanetary magnetic field strength remained below 5 nT, and the southward component ranged between -5 nT and +5 nT. On May 26, 2019, at 21:25 UT, a jump in the solar wind was observed with the solar wind speed jumping from 300 km/s to 360 km/s. The interplanetary magnetic field strength also increased rapidly and reached 12 nT, while the southward component reached -9.5 nT. This observed solar wind structure is probably associated with the arrival of an interplanetary CME, however, the CME could be accurately identified earlier in coronagraph imagery. One possible candidate could be the narrow and slow CME observed in STEREO-COR2 images on May 22 at around 04:30 UT. Solar wind parameters are expected to return to nominal values for a short time after the passage of this solar wind structure. Then it is expected to be re- enhanced tomorrow on May 28, with the arrival of the fast solar wind associated with the negative polarity equatorial coronal hole which began to traverse the central meridian on May 24.

The geomagnetic conditions have been quiet during the beginning of the period. It became unsettled (with Kp index (NOAA) and local K index (Dourbes) = 3) due to the jump into the solar wind parameters. Active conditions with intervals of K-Dourbes = 4 are possible on May 28, due to the expected arrival of a high-speed solar wind stream associated negative polarity equatorial coronal hole.

Today's estimated international sunspot number (ISN): 000, based on 23 stations.

Solar indices for 26 May 2019

Wolf number Catania	///
10cm solar flux	068
AK Chambon La Forêt	012
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	000 - Based on 28 stations

Noticeable events summary

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

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