Viewing archive of Saturday, 30 September 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Sep 30 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
30 Sep 2023	160	015
01 Oct 2023	160	016
02 Oct 2023	160	014

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours was at low levels. The largest flare was a C9.6-flare, with peak time 11:57 UTC on September 30, associated with a yet unnumbered active region which is rotating over the east limb in the northern hemisphere and the second largest flare was a C8-flare, with peak time 06:00 UTC on September 30 which was associated with NOAA AR 3445. Both of these regions produced most of the flaring activity in the last 24 hours. There are currently 6 numbered active regions on the visible disk, NOAA AR 3449 (beta-gamma) and NOAA AR 3450 (beta-gamma) have both grown in size, all other regions have simple alpha or beta magnetic field configurations. The solar flaring activity is likely to be at low levels over the coming days with C-class flares expected, M-class flares possible and a low chance for isolated X-class flaring.

Coronal mass ejections

No Earth-directed CMEs have been detected in the last 24 hours. A CME was seen erupting towards the north-east in LASCO-C2 data from 04:44 UTC on September 30 this CME is determined to be back-sided and is not expected to impact the Earth.

Coronal holes

A positive polarity coronal hole has passed the central meridian in the northern hemisphere. Another positive polarity coronal hole is starting to pass the central meridian at the equator.

Solar wind

In the last 24 hours, the interplanetary magnetic field fluctuated between 5 nT and 8 nT. The Bz fluctuated between positive and negative values with a minimum value of – 6 nT. The solar wind speed had values varying between 388 km/s and 487 km/s. The phi-angle was mainly in the positive sector (directed away from the Sun). Slow solar wind conditions are expected in the next 24 hours with a possible high speed stream influence from late on September 30, associated with the positive polarity coronal hole that began to cross the central meridian on September 27.

Geomagnetism

The geomagnetic conditions over the past 24 hours were active globally (Kp 4) and locally (K Bel 4). Quiet to unsettled conditions are expected in the next 24 hours with active conditions possible from October 1.

Proton flux levels

The greater than 10 MeV proton flux was at background level over the last 24 hours and is expected to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES-16 went above the 1000 pfu threshold value between 10:55 UTC and 02:50 UTC on September 30. The greater than 2 MeV electron flux is expected to increase above the threshold again in the next 24 hours. The 24h electron fluence was at moderate levels and is expected to remain at moderate levels in the next 24 hours.

Today's estimated international sunspot number (ISN): 125, based on 18 stations.

Solar indices for 29 Sep 2023

Wolf number Catania	113
10cm solar flux	155
AK Chambon La Forêt	014
AK Wingst	010
Estimated Ap	010
Estimated international sunspot number	114 - 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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