Summary and Forecast

Solar Summary

(last updated 13 May 2024 23:30 UT)

Activity 13 May: R2 Flares Max Fadeout Freq. Sectors M1.1 12/2206UT possible lower East Pacific/ North American M1.0 12/2310UT possible lower West Pacific M1.2 0133UT possible lower West Pacific M1.3 0820UT possible lower Mid East/Indian M4.9 0933UT possible lower Mid East/Indian M6.6 0944UT probable lower Mid East/Indian M1.0 1747UT possible lower South American/ Atlantic M1.6 2159UT possible lower East Pacific/ North American Observed 10.7 cm flux/Equivalent Sunspot Number for 13 May: 215/165

Solar Forecast

(last updated 13 May 2024 23:30 UT)

14 May 15 May 16 May Activity R1-R2, chance R3 R1-R2, chance R3 R0-R1 Fadeouts Probable Probable Probable 10.7cm/SSN 215/165 200/152 190/143 COMMENT: Solar activity on UT day 13-May was at the R2 level due to a long duration M6.6 flare at 13/0944UT. Several M-class flares at the R1 level were also observed during the UT day. AR3664 (S20W86, beta-gamma-delta) remains the largest, most complex and most active sunspot region on the solar disk. This region was responsible for the vast majority of the M-class flares on 13-May. AR366 has partially rotated off the solar disk and is expected to rotate off completely over 14-15 May. AR3670 (N14W22, beta), AR2676 (S21W03, beta), AR3679 (S09E60, beta) and newly numbered region AR3681 (S09W17, beta) all showed spot development over the UT day. AR3674 (S13E39, beta) was stable, but was associated with an M4.5 flare at around 13/1046UT mostly obscured by the declining background of the long duration M6.6 flare at 13/0944UT. All other sunspot groups are either stable or in decay. Solar activity is expected to be at R1-R2 levels over 14-15 May, with a chance of G3. R0-R1 conditions are expected on 16-May once AR3664 has rotated completely off the solar disk. S1 solar radiation conditions were observed from 13/1355UT following the long duration M6.6 flare at 13/0944UT. S1 conditions are expected to persist into 14-May before declining below the S1 level by 15-16 May. A fast, partial halo CME is visible in SOHO imagery from 13/0924UT associated with the long duration M6.6 flare at 13/0944UT. Modelling indicates a component of this CME will impact Earth on 15-May at 0400UT +/- 12 hours. Another on disk eruption is visible from 13/1015UT in H-Alpha, SDO and GOES SUVI imagery, associated with the M4.5 flare produced by AR3674 at around 13/1046UT. No associated CME is visible in available coronagraph imagery. The solar wind was in decline on UT day 14-May as remaining CME impact effects waned. The solar wind speed ranged from 850 to 526 km/s and is currently near 575 km/s. The peak total interplanetary field strength (IMF, Bt) was 10 nT and the north-south IMF component (Bz) range was +7 to -6 nT. The solar wind is expected to continue to decline towards background levels over 14-May. An increase is expected on 15-May due to an anticipated impact from a CME first observed on 13-May.

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