Summary and Forecast

Solar Summary

(last updated 16 Oct 2026 23:30 UT)

Activity 16 Oct: R1 Flares Max Fadeout Freq. Sectors M1.3 1542UT possible lower South American/ Atlantic Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Oct: 131/85

Solar Forecast

(last updated 16 Oct 2026 23:30 UT)

17 Oct 18 Oct 19 Oct Activity R1 R1 R1 Fadeouts Possible Possible Possible 10.7cm/SSN 130/84 125/78 125/78 COMMENT: Solar flare activity reached the R1 level on UT day 16-Oct, due to an M1.3 flare peaking at 16/1542UT from Active Region (AR) 4551 (S15W17, beta-gamma-delta). This region is the largest and most magnetically complex of three regions on the solar disk, and has continued to exhibit minor spot development over the previous UT day. Region 4557 (N08E17, beta-gamma) has also exhibited growth and increased in magnetic complexity over the same period. The remaining region, AR 4555 (S08W68, alpha), remains stable. Solar flare activity is forecast to be at the R1 level over 17-19 Oct, given the recent growth of AR 4557 in addition to the recent flare history of AR 4551. S0 solar radiation storm conditions were observed over 16-Oct, with the proton flux consistent with background. S0 solar radiation storm conditions are forecast over 17-19 Oct. No geoeffective coronal mass ejections were observed over the previous UT day in available coronagraph imagery. Two CMEs were visible in SOHO/LASCO imagery over the past 24 hours; however, both were determined to be farside events. The solar wind speed was broadly stable over the previous UT day, ranging between 430 km/s and 490 km/s across the UT day. The interplanetary magnetic field strength (IMF, Bt) peaked at 6 nT, with the north-south component (Bz) ranging between -6 and +6 nT over the UT day. The solar wind speed is forecast to slowly decline over 17-18 Oct, before a mild increase in the solar wind speed is forecast on 19-Oct due to a high speed wind stream from an equatorial coronal hole.

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