Viewing archive of Saturday, 18 March 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Mar 18 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
18 Mar 2023	138	007
19 Mar 2023	140	019
20 Mar 2023	138	029

Bulletin

The solar flaring activity was at moderate levels during the last 24 hours with one M-class flare and several C-class flares detected, with the most frequent sources being NOAA active regions 3254 and 3256. The largest flare was a M1.1 flare, peaking at 15:07 UTC on March 17, associated with active region NOAA 3254 (beta class). NOAA active region 3256 produced an impulsive C9.4 flare at 07:10 UTC on March 18. This event was also associated with Type IV radio emission. Other regions on the disc did not show any significant flaring activity. Further M-class flare activity is possible but not probable, while frequently C-class activity is expected in the next 24 hours.

A filament eruption in the southwestern quadrant was observed on March 17 from around 09:20UTC. The associated CME appears in SoHO/LASCO C2 coronagraph data from 10:23UTC onwards. The CME is directed to the south- west and the bulk of the CME is not expected to be Earth directed. However, a glancing blow of the shock may impact Earth at around 19:00 UTC on March 19. Another small filament eruptions occurred in the northernwestern quadrant from around 17:09UTC and 20:09UTC on March 17. We are awaiting corresponding coronagraph data for further analysis. During the last 24 hours there were no other potentially Earth-directed CMEs detected in the available coronagraph observations.

The greater than 10 MeV proton flux was at almost nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux remained 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 normal levels and is expected to remain so.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) have been indicative of slow solar wind conditions. The solar wind speed ranged between 400 km/s and 450 km/s. The interplanetary magnetic field magnitude was about 6 nT. The magnetic field orientation was predominantly in the positive sector (field directed away from the Sun). Similar slow solar wind regime is expected on March 18 with a slight wind speed enhancement possible for late on March 19, due to expected influence of the small equatorial coronal hole of positive polarity with a chance of being mixed with glancing blow from a CME which left the solar surface around 10 UTC on March 17th.

The geomagnetic conditions over the past 24 hours were globally and locally quiet to unsettled (NOAA Kp and K Bel 1-3). Quiet conditions are expected for Mach 18 with active to minor storm conditions possible for late on March 19 and March 20, due to expected arrival of the high speed stream and a possible glancing blow from a CME.

Today's estimated international sunspot number (ISN): 044, based on 14 stations.

Solar indices for 17 Mar 2023

Wolf number Catania	110
10cm solar flux	134
AK Chambon La Forêt	014
AK Wingst	007
Estimated Ap	007
Estimated international sunspot number	073 - Based on 18 stations

Noticeable events summary

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

All times in UTC

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