Viewing archive of Monday, 27 February 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Feb 27 1255 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
27 Feb 2023	159	043
28 Feb 2023	159	019
01 Mar 2023	159	017

Bulletin

The solar flaring activity returned to low levels of the past 24 hours. Only C-class flares were observed. The larger flare was a C5.5-class flare from NOAA active region 3235 on Faburary 26 peaking at 12:00 UTC. NOAA active region 3234 remained quiet and seems to be stable, but continues to be the most complex region on disc. The other regions were stable or in decay. The flaring activity over the next 24 hours is expected to remain mostly at low levels with C-class flares, and low possibility of M-class flare.

Several coronal mass ejections and flows were observed in the currently available SOHO/LASCO coronagraph imagery and automatically detected by the Cactus tool over the past 24 hours. No clear Earth-directed coronal mass ejections were identified. The asymmetric halo CME associated to the M6.3 flare appearing in the SOHO/LASCO-C2 field of view on February 25 at 19:36 UTC was estimated to have an Earth directed component given the source location on disc and the halo extent in coronagraph images the CME. The model runs indicate an estimated arrival later today around 18:00 UTC February 27.

The greater than 10 MeV protons flux slowly returned below the 10 pfu threshold over the past 24 hours. The proton flux is expected to return to the background levels over the next day before. The greater than 2 MeV electron flux was below the 1000 pfu threshold and is expected to remain below this threshold over the next days. The 24-hour electron fluence was at normal levels and is expected to be at normal levels over the next 24 hours.

The solar wind environment near Earth was under the influence of a slow wind regime. On February 26, around 18:00 UTC the solar wind start to be enhanced. A shock was observed at 18:43 UTC with solar wind speed jumping from 479 km/s to 547 km/s and the total interplanetary magnetic field jumping from 9 nT to 19 nT. This marked the expected arrival of the CME that left the Sun on February 24. Solar wind speed has meanwhile further increased to over 700 km/s. The southward interplanetary magnetic component, Bz, has been mostly southward reaching to -18 nT. Currently, starting from 10:30 UTC, the solar wind has further increased to reach 830 km/s. Further data is needed to assess the origin of this increase, it could indicate the expected the arrival of the February 25 CME, or the high-speed stream from the equatorial negative polarity coronal hole, or a combination of both effects.

Geomagnetic conditions have reached moderate to major storm levels (K-BEL=5, and Kp-NOAA=7). Further episodes of moderate geomagnetic storming can be expected as the CME passes.

Today's estimated international sunspot number (ISN): 150, based on 14 stations.

Solar indices for 26 Feb 2023

Wolf number Catania	///
10cm solar flux	159
AK Chambon La Forêt	048
AK Wingst	029
Estimated Ap	027
Estimated international sunspot number	141 - 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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