Viewing archive of Saturday, 22 September 2018

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2018 Sep 22 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
22 Sep 2018	067	018
23 Sep 2018	067	011
24 Sep 2018	066	008

Bulletin

There are presently no sunspot groups observed on the visible side of the Sun. Accordingly, no flares were reported during last 24 hours and we expect such a quiet conditions to persist in the coming hours. No Earth directed CMEs were observed, and the solar protons remained at the background level.

The in situ observations indicate arrival of the fast solar wind associated with the low latitudinal extent of the northern polar coronal hole. The interplanetary magnetic field magnitude started to increased simultaneously with the density increase and the change of the phi angle in the late evening of the September 21. After about 23:00 UT on September 21, density decreased and solar wind speed started to increase simultaneously with the increase of the temperature. The solar wind speed is presently about 470 km/s and the interplanetary magnetic field magnitude is about 10 nT. The arrival of one more fast flow, associated with patchy equatorial coronal hole which reached central meridian on September 18, is expected this evening. The arrival of the fast solar wind induced disturbed geomagnetic conditions yesterday evening and this morning. Local station at Dourbes reported intervals of K=4 at about 03:00 UT this morning, while NOAA reported two intervals of Kp=5 starting from about 21:00 UT yesterday up to 03:00 UT this morning. Presently geomagnetic conditions are unsettled to active and we expect such a disturbed geomagnetic conditions to remain the coming hours. We might expect also isolated intervals of minor storm conditions starting from late this evening due to arrival of the fast flow associated with the equatorial coronal hole.

Today's estimated international sunspot number (ISN): 000, based on 20 stations.

Solar indices for 21 Sep 2018

Wolf number Catania	000
10cm solar flux	067
AK Chambon La Forêt	028
AK Wingst	009
Estimated Ap	011
Estimated international sunspot number	000 - Based on 32 stations

Noticeable events summary

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

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