Summary and Forecast

Solar Summary

(last updated 20 Jan 2025 23:30 UT)

Activity 20 Jan: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Jan: 230/180

Solar Forecast

(last updated 20 Jan 2025 23:30 UT)

21 Jan 22 Jan 23 Jan Activity R1-R2 R1-R2 R1-R2 Fadeouts Possible Possible Possible 10.7cm/SSN 225/175 225/175 225/175 COMMENT: Solar activity on UT day 20-Jan was R0. Solar region AR3961 (S10W06, beta-gamma) is currently the largest region on the solar disk but has been recently flare quiet. The trailer spots of this region have redistributed with an increase in separation, along with growth in intermediate penumbral area and the umbral area of the leader spot appears to have also reduced/redistributed, possibly indicating this region is in initial decay. Other regions of note, medium sized region AR3959 (N19W28, beta) which consists mainly of a large spot and AR3964 (N11W73, beta-gamma) which is approaching the western solar limb, have also been generally stable and relatively flare quiet with AR3959 producing a single C class flare. More minor solar region AR3968 (S18W79, beta) produced several C class flares, the largest a C6.3 at 20/1315UT. Small solar regions AR3965 (N16E16, beta) and AR3969 (S06E49, beta) have shown minor growth. There are currently ten numbered sunspot regions on the solar disk. Other regions are either stable or in decay. A 10 degree long solar filament located at S05E40 partially erupted at 20/0525UT, with the small filament appearing to erupt then reform. Another small 8 degree long solar filament located at S15E35 erupted at 20/1946UT. Solar activity is expected to be R1-R2 over 21-23 Jan. S0 solar radiation storm conditions were observed on UT day 20-Jan. S0 solar radiation storm conditions are expected over 21-23 Jan. No significantly Earth directed CMEs have been observed. A minor southeast non Earth directed CME was just becoming visible from 20/2112UT in LASCO C2 imagery probably in association with the second small filament eruption. The solar wind environment on UT day 20-Jan was moderate to strong due to the ongoing influence of a coronal hole wind stream, with an increase in wind speed observed during the second half of the UT day. The solar wind speed ranged from 660 to 460 km/s, and is currently near 660 km/s. The peak total interplanetary field strength (IMF, Bt) was 9 nT and the north-south IMF component range (Bz) was +9 to -7 nT with the IMF Bz component frequently oscillating southwards. The solar wind speed is expected to remain moderately elevated on 21-Jan then with an overall gradual declining trend over 22-23 Jan. A CME from 18-Jan may have a weak glancing impact on 21-Jan, but this is mostly expected to pass ahead of the Earth.

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