Viewing archive of Thursday, 27 July 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Jul 27 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
27 Jul 2023	171	008
28 Jul 2023	168	005
29 Jul 2023	165	004

Solar Active Regions and flaring

Solar flaring activity was moderate during the last 24 hours, with a double-peaked M2 flare detected from NOAA Active Region (AR) 3376 (magnetic type Beta, Catania group 85) yesterday (brightest peak at 15:59 UTC) and an also double-peaked M1 flare from the same NOAA AR today (brightest peak at 09:51 UTC). A number of bright C-class flares was also detected in the last 24 hours, a C9 and a C5 from NOAA AR 3376, a C6 from NOAA AR 3380 (magnetic type Beta, Catania goup 95), a C4 and a C3 from a yet-unnamed AR at N24E87, and a C3 from a yet-unnamed AR at S23E87. Although numerous more C-class flares were detected with lower intensity from NOAA AR 3376, it is no expected to produce many more detectable flares in the next 24 hours as it is currently moving behind the solar limb. However, NOAA AR 3380 and the two unnamed AR are expected to produce C-class and possibly M-class flaring activity in the next 24 hours.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CME) were observed in the last 24 hours.

Solar wind

A High Speed Stream (HSS) arrived yesterday at 16:00 UTC as predicted. The Solar Wind (SW) speed increased from 500 km/s to 600 km/s as a result of the HSS, but it has gradually dropped to 450 km/s since. The total interplanetary magnetic field (Bt) varied between 5 and 7 nT and its North-South component (Bz) ranged between -5 and 5 nT. The interplanetary magnetic field phi angle changed from being directed towards the Sun before the arrival to being directly away from the Sun after the event. Since the HSS has a relatively slow SW speed which has already decreased significantly, the SW conditions are expected to return to a slow wind regime within the next 24 hours.

Geomagnetism

Geomagnetic conditions were both globally and locally quiet to unsettled (NOAA Kp 2- to 3+ and K BEL 1 to 3) during the past 24 hours. They are expected to be mostly quiet with short periods of unsettled conditions in the next 24 hours.

Proton flux levels

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

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by the GOES-16 satellite, was at increased levels during the last 24 hours as a result of the arrival of a HSS. Nevertheless, the flux remained well below the 1000 pfu alert threshold and is expected to remain below this threshold during the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain so during the next 24 hours.

Today's estimated international sunspot number (ISN): 134, based on 08 stations.

Solar indices for 26 Jul 2023

Wolf number Catania	178
10cm solar flux	167
AK Chambon La Forêt	020
AK Wingst	020
Estimated Ap	022
Estimated international sunspot number	149 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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