Space Weather Forecast Headline: Coronal Mass Ejections (CMEs) undergoing analysis, otherwise falling slight chance of further Minor Geomagnetic Storm G1s.

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Activity was Moderate, with a solitary Moderate-class X-ray flare from a growing sunspot region nearing the middle of the Sun at 21/1827UTC, followed by a period of enhanced Common-class flaring that has since eased.

There are currently up to seven sunspot regions on the facing side of the Sun, with a new magnetically unipolar spot becoming visible near the eastern solar horizon, and with a second, larger region here perhaps better split into two clusters by solar latitude. Amongst the most notable changes in the period were seen in the region responsible for the peak flare, which saw strong proliferation in its leading spots, later hollowing out into a ring shape. The northeastern sunspot regions continued to display a very diffuse appearance, with numerous well-dispersed small pores and spots developing and fading. The northeastern quadrant also harboured the largest region on the facing side, which saw growth of its trailer and minor intermediate spots, as well as strong growth to its immediate south as a likely new region emerged and spread.

There has been some 'filament' (arc of plasma) activity in the northeast in the period. Firstly, around 22/0400UTC, a Coronal Mass Ejection (CME) was emitted (as evidenced on extreme UV imagery). The resultant Coronal Mass Ejection (CME) has been analysed as a slow feature largely east of the Sun-Earth line, but perhaps narrowly glancing Earth at the very end of the period (late Thursday 25 December). At 22/0850UTC, a filament eruption was then observed in ground-based near-infrared imagery (e.g. Udaipur observaroty, India). Imagery of the resulting CME is awaited. A final slow disappering filament was noted (on e.g. Learmonth observatory imagery, Australia) at 22/0930UTC from north of the largest sunspot region, with imagery again awaited.

Solar Wind / Geomagnetic Activity: The solar wind showed a maturing connection to the fast wind from a large 'coronal hole'. The solar wind speed was strong and showed a slight rise in the 24 hours, whereas the number of particles in the solar wind was level within typical background. The magnitude of the solar wind magnetic field was slightly elevated, but this reduced with time. The north-south component was erratic, with no protracted co- or anti-aligned periods (with Earth's field, to usual lesser or greater geomagnetic effect, respectively).

The net result of the above solar wind measures was for provisional early peak Minor Geomagnetic Storm G1 conditions at 12-15 and 21-24UTC. Activity has since fallen to become largely quiet.

Energetic Particles / Solar Radiation: No solar radiation storms were observed.

Four-Day Space Weather Forecast Summary

Solar Activity: Increased activity has led to a now raised daily chance of Moderate-class flares and slight chance of Strong-class. These risks may rise slightly at the very end of the period with the potential return of the vanguard spots of a large, complex and previously 'productive' region - should it have survived the crossing of the far side.

Solar Wind / Geomagnetic Activity: No CMEs currently feature in the forecast, however recent filament activity on the northeast of the Sun may yet revise this, with analyses pending.

Otherwise, the incumbent fast wind should now be in a maturing phase, with a very gradual decline through to midweek UTC now expected. There is a residual slight chance of further G1 Minor Storm intervals should protracted anti-aligned solar wind magnetic field develop (with Earth's field), otherwise increasingly quiet conditions should become predominant from midweek UTC.

Energetic Particles / Solar Radiation: No solar radiation storms are expected given the strong eastern solar hemisphere bias in sunspot region populations (connecting less well with Earth should they flare appropriately).