Space Weather Forecast Headline: Chance of G2/Moderate storms Day 2 (09 Oct). Daily Chance of R1 Minor radio blackouts. 

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Solar activity is now at Low levels, with only Common-class flares observed in the past 24 hours. The peak being a C7.9 flare at 07/1317 UTC. There are currently four sunspot regions on the visible disc. The largest and most complex is near centre disc, which continues to show magnetic complexity, though appears to be generally stable in size. Another sunspot region, lying just to its northwest, is a smaller region, although this has recently increased in complexity too. The other regions are relatively simple sunspot regions.

A Coronal Mass Ejection (CME) associated with the peak flare was observed in imagery, which looks to give a glancing blow on Day 3 or 4 (10-11 Oct). No other earth directed CMEs have been observed. 

Solar Wind / Geomagnetic Activity: Solar winds, as measured by SOLAR-1 at L1, suggest that Earth is now outside of the influence of the coronal hole fast winds. The solar wind speed has reduced from Slightly Elevated at 420km/s down to Background at 360-370km/s. The Interplanetary Magnetic Field, Bt, was Weak. The north-south component, Bz, was generally southward (negative). Geomagnetic activity was Quiet to Unsettled (Kp 1-3).

Energetic Particles / Solar Radiation: GOES18 10MeV proton flux has been predominantly at resting Background values.

Four-Day Space Weather Forecast Summary

Solar Activity: This is expected to be Low to Moderate, with a chance of Moderate-class activity from the more complex sunspot regions. These regions should remain on the Earth-facing disc throughout the next few days, with no significant returning regions otherwise due. This means there is an overall flat trend for a daily Chance of Moderate-class and very slight Chance of Strong flares.

Solar Wind / Geomagnetic Activity: The 06 Oct CME has been analysed with an arrival time most likely in the early UTC hours of Day 2 (09 Oct). There was a CME associated with the C7.9 flare at 07/1317 UTC, which has been analysed to give a glancing blow late on Day 3 (10 Oct) or early Day 4 (11 Oct).

Solar wind speeds have now declined to background levels, following the waning connection to the fast winds from a coronal hole. Other coronal hole influence is now unlikely to be a significant factor in the forecast, with two Earth-directed CMEs.

Geomagnetic activity is expected to be mostly Quiet on Days 1 (08 Oct), with a Slight Chance of G1/Minor Storm perhaps late Day 1 (08 Oct) if the CME arrives early. During Day 2 (09 Oct), with the expected CME arrival, conditions are likely to be Active to G1/Minor storm, with a chance of G2/Moderate storm intervals and a slight chance of G3/Strong storm intervals. These effects should span the remainder of Day 2 (09 Oct), before easing on Day 3 (10 Oct). However, if the 07 Oct CME arrives late on Day 3, this will keep conditions Unsettled to Active (Kp 3-4) with a chance of G1/Minor storms (Kp 5) and a slight chance of G2/Moderate storms (Kp 6). This CME is only a glancing blow and so the effects should be less than the early CME. While there is uncertainty with regards timing, by the end of Day 4 (11 Oct) it should ease back towards Quiet to Unsettled (Kp 1-3) with some Active (Kp 4) intervals and a reducing chance of G1/Minor storms (Kp 5).

Energetic Particles / Solar Radiation: There is a daily Slight Chance of S1 Minor Solar Radiation Storms, with this gradually increasing due to the westward progression of the two most complex sunspot regions.