Viewing archive of Wednesday, 18 October 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Oct 18 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
18 Oct 2023	135	013
19 Oct 2023	135	008
20 Oct 2023	133	011

Solar Active Regions and flaring

The solar flaring activity was at low levels. There are currently three numbered active regions on the solar disk. The region on the north east limb is not yet numbered and remains very small and simple. NOAA AR3465 is the most complex region on the disk, but has been quiet. The remaining regions were mostly simple and were quiet. NOAA AR3463 decayed into a plage region. The solar flaring activity is expected to be at low levels over the next 24 hours with C-class flares likely and a low chance for isolated M-class flares.

Coronal mass ejections

The Coronal Mass Ejection (CME) reported yesterday, first observed from 05:17 UTC in SOHO/LASCO-C2 to the south-west is predicted to be mostly directed to the south of the Sun-Earth line. The CME is also relatively slow (around 400 km/s) but may have a glancing blow at Earth late on October 21. A wide partial halo CME, seen in SOHO/LASCO-C2 from 02:30 UT October 18 - directed mostly to the north-east, is determined to be back-sided and will not impact Earth.

Solar wind

The solar wind parameters reflected a slow solar wind regime at the start of the period. From 02:30 UTC on October 18, the solar wind parameters showed the likely influence of the solar wind from the positive polarity coronal hole, which crossed the central meridian on October 14. The interplanetary magnetic field increased, reaching 10nT by 11 UTC. Bz had a minimum value of -9 nT. The solar wind speed increased from 300 km/s to near 400 km/s. The interplanetary magnetic field orientation switched from the predominantly in the negative sector to the positive sector (field directed away from Sun). The solar wind parameters are expected to remain slightly enhanced over the next days under the influence of a weak high- speed stream. Additionally further enhancements may be possible on October 20 due to the glancing blow predicted for the CME of October 16.

Geomagnetism

During last 24 hours the geomagnetic conditions were at quiet to unsettled levels (NOAA KP 1-2 and K Bel 1-3). Geomagnetic conditions are expected to be at unsettled to active levels on October 18. Active intervals are also possible on October 20 due to the glancing blow predicted for the CME of October 16.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux remained below the 1000 pfu threshold as measured by GOES 16. It is expected to remain below this threshold over the next days. The 24 hour electron fluence was at nominal levels. The electron fluence is expected to be at nominal levels for the next days.

Today's estimated international sunspot number (ISN): 068, based on 09 stations.

Solar indices for 17 Oct 2023

Wolf number Catania	116
10cm solar flux	137
AK Chambon La Forêt	007
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	071 - 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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