Viewing archive of Monday, 24 April 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Apr 24 1237 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
24 Apr 2023	133	051
25 Apr 2023	140	018
26 Apr 2023	145	010

Bulletin

Solar flaring activity was low and infrequent during the last 24 hours. Three C-class flares were detected, all from NOAA Active Region (AR) 3282 (magnetic type Beta-Gamma, Catania group 61). Further C-class activity is likely in the next 24 hours, either from NOAA AR 3282 or NOAA AR 3285 (magnetic type Beta, Catania group 65).

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

The greater than 10 MeV proton flux exceeded the 10 pfsu level yesterday between 18:15 and 18:40 UT and stayed at nominal levels for the rest of the past 24 hours. In the next 24 hours it is expected to remain below the 10 pfsu level. 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 nominal levels and is expected to remain so.

A small equatorial coronal hole of negative polarity started crossing the central meridian today. An associated high speed stream in in-situ solar wind measurements is expected for 28 April.

The Solar Wind (SW) conditions are strongly affected by the arrival of a Corona Mass Ejection (CME) as previously forecasted. The SW speed increased from 340 to km/h before the arrival of the CME to 650 km/h by today 01:00 UT. The total interplanetary magnetic field (Btot) increased to 35 nT yesterday at 17:00 UT, while its North-South component (Bz) dropped as low as -33 nT. The interplanetary magnetic field phi angle was predominantly directed towards the Sun over the last 24 hours. For the next 24 hours the SW speed and the Btot are expected to remain high, however the Bz has already increase above zero and is not expected to predicted to dropped to such low values in the next 24 hours.

Geomagnetic conditions reached globally severe storm (Kp 8 between 18:00-21:00 UT yesterday and 03:00-06:00 UT today, Kp 8- between 21:00-00:00 yesterday) and strong storm (Kp 7 between 00:00-03:00 and Kp 7- between 06:00-09:00 today), while the rest of the time they were at minor to moderate storm levels. Locally the situation was rather similar, with K BEL at storm level (K BEL 5 or more) since yesterday 21:00 UT. Storm levels are expected for the next several hours and a significant decrease for the rest of the next 24 hours, both globally and locally.

Today's estimated international sunspot number (ISN): 077, based on 09 stations.

Solar indices for 23 Apr 2023

Wolf number Catania	///
10cm solar flux	135
AK Chambon La Forêt	103
AK Wingst	062
Estimated Ap	055
Estimated international sunspot number	087 - Based on 16 stations

Noticeable events summary

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

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