Viewing archive of Friday, 27 September 2019

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2019 Sep 27 1230 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
27 Sep 2019	068	011
28 Sep 2019	068	028
29 Sep 2019	068	021

Bulletin

Solar X-ray flux remained below B class levels throughout the period. The Solar disk is spotless and the X-ray flux is expected to remain at or below background levels.

There were no Earth-directed Coronal Mass Ejections (CME) observed in coronagraph data.

Proton levels were at background values and are expected to remain so.

The solar wind speed has decreased from 440 and 400 km/s over the past 24 hours. The total magnetic field strength has fluctuated between 1 and 4 nT. The Bz ranged between -3 and 2 nT, but was mainly positive. Geomagnetic conditions ranged between Kp index 0-2 (NOAA) and local K index 0-2 (Dourbes).

The solar wind conditions declined over the past 24 hours as we moved to background solar wind conditions following the passing of a small high speed stream (HSS). However, a small Fast Forward shock in the solar wind was detected today at 04:50 UT. The magnetic field jumped from 1 to 4 nT and the solar wind speed from 340 km/s to 370 km/s. The origin is not clear, and the relatively small size of the jump had no consequence on the K/Kp levels at Earth.

Later today and tomorrow we expect solar wind conditions to become enhanced due to the presence of a HSS from a large recurrent coronal hole, which passed the central meridian two days ago. On the coronal hole's last rotation the resultant HSS produced minor storm conditions for short periods.

Today's estimated international sunspot number (ISN): 000, based on 16 stations.

Solar indices for 26 Sep 2019

Wolf number Catania	000
10cm solar flux	067
AK Chambon La Forêt	007
AK Wingst	004
Estimated Ap	003
Estimated international sunspot number	000 - Based on 19 stations

Noticeable events summary

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

All times in UTC

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