Viewing archive of Thursday, 20 July 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Jul 20 1231 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
20 Jul 2023	186	008
21 Jul 2023	190	013
22 Jul 2023	190	012

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours remained at moderate levels. The largest flare was a M3.8-flare, with peak time 17:25 UTC on July 19, produced by NOAA AR 3363. This region was the most active region in the last 24 hours producing both of the M-class flares that were detected and most of the C-class flares, however it has now rotated over the west limb. Not including NOAA AR 3363, there are currently 8 numbered active regions on the visible disk. NOAA AR 3376 was the second most active region producing two C-class flares. NOAA AR 3378 grew in size. Newly numbered active region NOAA AR 3379, has rotated onto the disk but has not produced significant flaring activity in the past day. The remaining active regions were quiet and stable. The solar flaring activity is likely to remain at moderate levels over the coming days with a low chance for isolated X-class flaring.

Coronal mass ejections

The coronal mass ejection (CME) to the north east seen in LASCO/C2 data from 20:12 UTC on July 18 has been analysed and is expected to have a possible glancing blow at Earth on the UTC afternoon of July 21. Two CMEs were observed in LASCO/C2 coronagraph data from 17:36 UTC on July 19 and from 23:12 UTC on July 19 to the north west. This first CME was associated, with an M3.8-class flare from NOAA AR 3363 both are not expected to arrive to earth.

Solar wind

The solar wind speed decreased from 431 km/s to values around 360 km/s. The magnetic field had a peak value of 6 nT. In the last 24 hours the Bz was manly positive with a minimum Bz of -3 nT. The phi angle was negative during the last 24 hours. Generally similar slow solar wind conditions are expected with enhancements possible on July 20 and 21, from the expected ICME arrivals.

Geomagnetism

The geomagnetic conditions over the past 24 hours were quiet (NOAA KP = 2, K-Bel = 2). Mostly unsettled conditions are expected over the next two days with isolated active to minor storm periods possible, due to the predicted CME arrivals.

Proton flux levels

The greater than 10 MeV proton flux has gradually been decreasing over the last 24 hours crossing below the 10 pfu threshold around 06:00 UTC on July 20. The proton flux is expected to continue to decrease in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES-18 crossed the 1000 pfu alert threshold at 17:00 UTC on July 19 and dipped below threshold values at 01:00 UTC on July 20. The greater than 2 MeV electron flux measured by GOES-16 remained below the threshold. The electron flux is expected to cross the threshold again in the next 24 hours. The 24h electron fluence was at nominal to moderate levels and is expected to be at nominal to moderate levels in the next 24 hours.

Today's estimated international sunspot number (ISN): 172, based on 21 stations.

Solar indices for 19 Jul 2023

Wolf number Catania	205
10cm solar flux	189
AK Chambon La Forêt	008
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	165 - 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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