Summary and Forecast

Solar Summary

(last updated 29 May 2023 23:31 UT)

Activity 29 May: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 29 May: 154/109

Solar Forecast

(last updated 29 May 2023 23:31 UT)

30 May 31 May 01 Jun Activity R0-R1, chance R2 R0-R1, chance R2 R0-R1, chance R2 Fadeouts Possible Possible Possible 10.7cm/SSN 150/105 140/94 135/89 COMMENT: Solar activity on UT day 29-May was at R0 levels. The largest flare on the UT day was a double peaked C5.9 flare from AR3310(S20W79, alpha) from 1820 UT. There are currently 10 numbered sunspot regions on the solar disk. AR3315 (S17W31, beta), which featured in yesterday's forecast, has started to decay and has not produced any significant flares over the 24 hour period. AR3317 (N28W37, beta), AR3318 (N25W30, beta) and AR3319 (S17E02, beta) have all shown rapid growth. All other sunspot regions are either stable or in decay. Solar activity is expected to be at R0-R1 levels over 30-May to 01-Jun, with a chance for R2 flares. A slow moving northwest CME was observed in SOHO imagery from 29/0200 UT, but is likely a farside event and not geoeffective. No other CMEs were observed. The solar wind speed was on a general declining trend on UT day 29-May and ranged between 357 to 455 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 6 nT and the north-south IMF component (Bz) range was +5 to -4 nT. A large coronal hole in the southern solar hemisphere may increase solar wind speeds by 01-Jun, although given its southern latitudinal extent this is low confidence. Otherwise, the solar wind speed is expected to remain near background levels over 30-May to 01-Jun.

Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.