Viewing archive of Tuesday, 26 September 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Sep 26 1322 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
26 Sep 2017	092	004
27 Sep 2017	094	016
28 Sep 2017	096	010

Bulletin

Solar activity slightly increased over the past 24 hours. Two numbered active regions (AR) regions on the visible disk AR 2681 (Cso; Beta), AR 2682 (Hax; Alpha), produced multiple B-class flares. The newly- numbered AR 2683 (Hkx; Apha) produced the largest C1.8 flare which peaked at 02:34 UT today (26-Sep-2017). One eruptive dimming has been observed at the solar disk center at 15:23 UT yesterday, an associated CME departed mostly toward the East with the projected speed around 490 km/s. More coronograph imagery is needed before conclusion can be made. One filament erupted from the east solar limb at 22:20 UT yesterday; the associated slow CME is not expected to be geoeffective. Solar activity is expected to remain low over the next 24 hours with a probability of C-class flares. Solar wind parameters returned to nominal levels during the past 24 hours. Solar wind speed decreased from around 400 km/s to 315 km/s. Total field strength remained below 3.5 nT, while Bz component varied between 2.5 and -2.5 nT. Solar wind parameters are expected remain at near background levels today (26-Sep-2017). Solar wind variations can increase tomorrow (27 September, 2017) due to the influence of the transequatorial positive polarity CH HSS. Geomagnetic conditions ranged between Kp index 0-2 (NOAA) and local K index 0-2 (Dourbes) over the past 24 hours. The geomagnetic field is expected to be at quiet levels today and may reach a minor storm level tomorrow (27-Sep-2017).

Today's estimated international sunspot number (ISN): 040, based on 18 stations.

Solar indices for 25 Sep 2017

Wolf number Catania	039
10cm solar flux	090
AK Chambon La Forêt	006
AK Wingst	005
Estimated Ap	004
Estimated international sunspot number	039 - Based on 29 stations

Noticeable events summary

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

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