Viewing archive of Tuesday, 18 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 18 1243 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 Apr 2023	166	004
19 Apr 2023	164	006
20 Apr 2023	164	013

Bulletin

Solar flaring activity was at low levels in the past 24 hours. The strongest activity was a C6.9 flare, peak time 14:31 UTC on April 17th, produced by NOAA AR 3283 (beta). There remain nine numbered regions on the visible solar disc. Most of the flaring activity was produced by NOAA AR 3282 (beta-gamma), which has reduced its size, but remains the largest active region on the visible disc, and increased its number of trailing spots. Multiple low C-class flaring was produced by NOAA AR 3280 (beta-gamma) from the west limb. Another notable active region on the visible disc is NOAA 3281 (beta- gamma), which was stable and inactive. The solar flaring activity is expected to be at low levels over the next 24 hours. Isolated M-class flaring remains possible.

No Earth-directed coronal mass ejections (CMEs) have been detected in the available coronagraph imagery.

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so in the next 24 hours. The greater than 2 MeV electron flux has been below the1000 pfu threshold and is expected to remain so. The 24h electron fluence was at nominal levels and is expected to remain so over the next 24 hours.

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were indicative of the influence of a weak stream originating from a positive polarity coronal hole. The solar wind velocity as measured by DSCOVR increased to almost 500 km/s, while ACE registered speeds up to 420 km/s. The interplanetary magnetic field reached a maximum value of 10.9 nT with a minimum Bz of -7.5 nT. The B field was in the positive sector (directed away from the Sun). The current slightly elevated solar wind conditions are expected to prevail until the first expected glancing blow arrival on April 19th.

The geomagnetic conditions over the past 24 hours were quiet. Mostly quiet to unsettled geomagnetic conditions are expected over the next 24 hours with possible, but unlikely isolated active periods.

Today's estimated international sunspot number (ISN): 138, based on 18 stations.

Solar indices for 17 Apr 2023

Wolf number Catania	190
10cm solar flux	167
AK Chambon La Forêt	010
AK Wingst	005
Estimated Ap	004
Estimated international sunspot number	152 - Based on 22 stations

Noticeable events summary

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

All times in UTC

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