Summary and Forecast

Solar Summary

(last updated 28 Feb 2026 23:30 UT)

Activity 28 Feb: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 28 Feb: 141/95

Solar Forecast

(last updated 28 Feb 2026 23:30 UT)

01 Mar 02 Mar 03 Mar Activity R0,chance R1 R0,chance R1 R0,chance R1 Fadeouts Possible Possible Possible 10.7cm/SSN 140/94 145/99 145/99 COMMENT: Solar activity on UT day 28-Feb was R0. There are three small to medium sized solar regions visible in the eastern solar hemisphere, AR4378 (N16E42, beta), AR4380 (S18E52, beta) and AR4381 (N08E66, beta). Solar region AR4380 has shown slight growth. An existing on disk region AR4379 has decayed and yesterday's new region was numbered AR4381. There are currently three numbered solar regions and one new unnumbered region on the solar disk. The new region is a very small spot at N28E04, which may be numbered if the spot persists. The largest flare for the day was a C6.4 flare at 28/0313UT from AR4380 with emission visible either side of the neutral line within this region. Solar regions AR4378 and AR4381 produced low level C class flares. Solar activity is expected to be R0, chance R1 over 01-03 Mar. Four small filament eruptions were observed on 28-Feb. The first at 28/0533UT located at N30E20 (with following minor on disk plasma motion at 28/0724UT), the second at 28/0543UT located at N22W28, the third at 28/1729UT located at S09W73 (associated with westward plasma ejecta) and the fourth at 28/1828UT located at N42E20 (which was the larger of the small filaments with a length of approximately 10 degrees). Due to the far westward location of the third filament and the relatively high north latitude location of the fourth filament these are not considered likely to be geoeffective. No significantly Earth directed CMEs were observed on UT day 28-Feb. However, LASCO space based coronagraph imagery was limited on 28-Feb with imagery only available later in the UT day. A north directed, out of the ecliptic plane CME is evident later in the UT day, probably associated with the filament eruption at N42E20. The STEREO-A spaced based coronagraph showed a narrow slow CME angled around 30-40 degrees northward out of the ecliptic plane from 28/0635UT, which may possibly be correlated with either of the two earlier small filament eruptions 28/0533UT at N30E20 or 28/0543UT located at N22W28. Due to the minor on disk plasma motion of the first event a model run was conducted using the available STEREO-A imagery assuming this location. This CME was modelled to have a speed of only 277 km/s and the ENLIL run showed no significant arrival at the Earth. S0 solar radiation storm conditions were observed on UT day 28-Feb. S0 solar radiation storm conditions are expected over 01-03 Mar. There are currently two polar/high latitude coronal holes crossing the solar central meridian in the northern and southern hemispheres. Due to the high solar latitude, small size and lack of equatorward extension these holes are considered insignificant. The solar wind speed exhibited a slight declining trend on 28-Feb as the influence of a solar coronal hole wind stream continues to gradually abate. The anticipated 28-Feb weak CME arrival was not evident in the solar wind parameters. A small disturbance was expected from a weak CME (filament eruption observed on 25-Feb) may possibly still arrive on 01-Mar, although confidence of this arrival is now low. The solar wind speed ranged between 380 and 456 km/s. The peak total interplanetary field strength (IMF, Bt) was 4 nT and the north-south IMF component range (Bz) was +4 to -4 nT. The solar wind speed is generally expected to continue to return to background levels over coming days.

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