Viewing archive of Monday, 25 September 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Sep 25 1312 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
25 Sep 2017	081	006
26 Sep 2017	083	008
27 Sep 2017	085	013

Bulletin

Over the past 24 hours solar activity has been low. No significant flares have been recorded. NOAA AR region 2681 (Catania group 55) has been most active, producing two B-class flares. No Earth directed Coronal Mass Ejections (CMEs) have been detected in coronograph observations. The greater than 10MeV proton flux remained at background levels over the past 24 hours. Solar activity is expected to remain low over the next 24 hours with a small probability of C-class flares.

The solar wind parameters remained at nominal levels over the past 24 hours (except one short-term weak enhancement around midnight due to the influence of a small negative polarity CH HSS). The solar wind speed is presently about 390 km/s and still decreasing. The total magnetic field strength has been slowly decreasing from around 10 nT to 2 nT. The Bz component fluctuated around 0 nT and was mainly positive, ranging between -3 and +2.5 nT (except two singular episodes of Bz = -6 and -9 nT yesterday evening). Geomagnetic conditions ranged between Kp index 1-3 (NOAA) and local K index 1-3 (Dourbes) over the past 24 hours. Geomagnetic conditions are expected to be from quiet to unsettled today and tomorrow. Active conditions till minor geomagnetic storms can be expected on September 27 due to the influence of a positive polarity CH HSS.

Today's estimated international sunspot number (ISN): 039, based on 22 stations.

Solar indices for 24 Sep 2017

Wolf number Catania	///
10cm solar flux	087
AK Chambon La Forêt	014
AK Wingst	006
Estimated Ap	006
Estimated international sunspot number	022 - Based on 24 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page