Viewing archive of Monday, 20 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 20 1257 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
20 Sep 2021	075	005
21 Sep 2021	076	004
22 Sep 2021	076	010

Bulletin

Solar flaring activity was at low levels, with a series of B class flares from region NOAA 2871, which is situated in the SE. Two unnumbered regions, of beta configuration are in North and NE . Solar activity is expected to remain at low levels, with a possibility of C class flares.

A filament eruption was observed in the South East on Aug 19 about 12:58UT, accompanied by a slow CME. Due to its location any impact is not expected to have significant effect.

The greater than 10 MeV proton flux was at background levels in the past 24 hours, and is expected to stay at nominal levels in the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold, while the 24h electron fluence was at nominal levels over the past 24 hours. Over the next 24 hours they are expected to remain at those levels.

Over the past 24 hours the solar wind speed was in the slow regime, varying between 295 to 350 km/s. The total magnetic field strength had values between 1 and 5 nT, while its Bz component varied between -3 and 4 nT. The interplanetary magnetic field phi angle was predominantly on the negative sector (directed towards the Sun), varying to the positive since Sep 20 07:00UT. This could indicate the influence of the beginning of the influence of the high speed stream of the positive coronal holes present in NW and SW. A negative Coronal Hole is about to cross the Central Meridian. Its effects can be expected at about Sep 23-24. Over the next 24 hours, solar wind conditions continue at about those levels, possibly slightly enhanced.

Geomagnetic conditions were at quiet to unsettled levels (NOAA Kp 0-1 and K Dourbes 0-2) over the past 24 hours. Quiet to unsettled conditions are expected over the next 24 hours.

Today's estimated international sunspot number (ISN): 041, based on 14 stations.

Solar indices for 19 Sep 2021

Wolf number Catania	///
10cm solar flux	075
AK Chambon La Forêt	006
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	013 - Based on 23 stations

Noticeable events summary

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

All times in UTC

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