Viewing archive of Friday, 18 August 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Aug 18 1241 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 Aug 2023	153	013
19 Aug 2023	151	014
20 Aug 2023	148	008

Solar Active Regions and flaring

The solar flaring activity was at low levels. The largest flare was a C5.1 flare peaking at 12:40 UTC on August 17, this originated near the west limb associated with NOAA AR3397, which has now rotated over the limb. NOAA AR 3403 decayed over the period and was quiet. NOAA AR3405 also produced C-class flares and has been split into two regions including the small new region NOAA AR3411. NOAA AR3407 and AR3410 were stable and quiet. NOAA ARs 3406, 3408 both decayed into plage region. NOAA AR3409, which began to emerge yesterday has continued to grow and produced low level C-class flares. 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

There were no Earth-directed Coronal Mass Ejections (CMEs) detected in the available coronagraph observations.

Solar wind

The solar wind parameters reflected a weak negative polarity high speed stream arrival. The interplanetary magnetic field was slightly enhanced, with a significant increase around 02:00 UTC on August 18, when it jumped from 9 and 14 nT. Bz had a minimum value of -11nT. The solar wind speed increased gradually from 02:00 UTC, from 300km/s to values near 500 km/s. The interplanetary magnetic field orientation switched to the negative sector (field directed towards the Sun) from 19:00 UTC on August 17. The solar wind parameters are expected to remain enhanced on August 18 and 19, while the Earth remains under the influence for the high-speed stream.

Geomagnetism

During last 24 hours the geomagnetic conditions were at quiet to unsettled levels (NOAA KP 1-3 and K-Bel 1-3). Geomagnetic conditions are expected to be at unsettled levels, with active periods possible on August 18 and 19, due to the ongoing high speed stream influence.

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): 125, based on 14 stations.

Solar indices for 17 Aug 2023

Wolf number Catania	///
10cm solar flux	152
AK Chambon La Forêt	011
AK Wingst	010
Estimated Ap	009
Estimated international sunspot number	149 - Based on 24 stations

Noticeable events summary

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

All times in UTC

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