Space Weather Forecast Headline: Chance of Minor Geomagnetic Storm G1 into UTC weekend and into new UTC working week.

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Activity is Low, with only Common-class flares observed in the past 24 hours. 

There are currently seven sunspot regions on the disc. The majority of these regions appear to be stable and magnetically unipolar regions. The main region of interest is currently located in the northwest, which has shown minor areal growth, with a rudimentary penumbral spot forming in the centre of the region. Another region located near centre-disc consists of a small cluster of spots, although has recently shown signs of decay. 

Satellite imagery in the period showed a faint emerging Coronal Mass Ejection (CME) signature from the western solar hemisphere from around 09/1600UTC. This has proven difficult to attribute to observed activity, and also to triangulate. A provisional assessment shows a weak feature as potentially arriving at Earth in the first half of the UTC day of Monday 14 September, i.e. beyond the four-day forecast horizon. This assessment will be revisited.

A more obvious 'filament' lift-off (arc of plasma leaving the Sun) occurred from the southwest (near S15W030) around 10/0315UTC. This has been analysed as missing ahead of Earth's orbit. 

Solar Wind / Geomagnetic Activity: Solar winds are currently at slightly elevated levels, ranging between 420-470km/s throughout the period, perhaps due to the tail-end of a minor transient feature. The Earth's magnetic field was mostly Weak, with the all important north-south component, Bz, also weakly negative (southward). Geomagnetic activity was Quiet to Unsettled (Kp 1-3). 

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

Four-Day Space Weather Forecast Summary

Solar Activity: Solar activity is expected to remain Low to Very Low. There is a gradual increasing slight chance of isolated Moderate-class x-ray flares, given up to two further regions' arriving over the eastern solar horizon over the UTC weekend.

Solar Wind / Geomagnetic Activity: The geomagnetic forecast is of low confidence, due to a non-recurrent 'coronal hole' fast wind and then a possible CME arrival on Day 4 (14 Sep).

All considered, there is a chance of Minor Geomagnetic Storm G1 from a coronal hole later Friday 11 September, and then a slight chance of G1 from a second coronal hole and any minor CME effects at the very end of Day 3 (13 Sep) with the full effects probably falling on Day 4 (14 Sep).

Energetic Particles / Solar Radiation: There is a slight chance of further enhancements above the S1/Minor Solar Radiation Storm threshold given the most active sunspot region's westward progress and development.