Space Weather Forecast Headline: R1/Minor Radio Blackouts likely. Chance of G1/Minor Geomagnetic Storm Days 2-3 (27-28 Aug).

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Solar activity has been Moderate over the past 24 hours with several Moderate-class flares from the large and complex region near the centre disc, the largest peaking at 25/1002 UTC.

There are currently four sunspot regions on the visible disc. The aforementioned region near the centre disc remains the most notable due to its magnetic complexity, with two clear delta spots. The other regions are relatively simpler with little to no activity observed at this point.

The recent Moderate-class flare that was emitted from the large and complex region near the centre disc produced an Earth-directed CME (Coronal Mass Ejection). A filament eruption followed shortly afterwards in the vicinity of the active region; however, analysis is still ongoing to determine its characteristics and potential Earth-directed component. filament eruption followed shortly afterwards; however, analysis is still ongoing to determine its characteristics and potential Earth-directed component.

Solar Wind / Geomagnetic Activity: Solar winds were indicative of a slow regime. Speeds were stable and around 320-350 km/s. Interplanetary Magnetic Field was weak, with the north-south component also varying weakly. Geomagnetic activity was Quiet (Kp0-1). 

Energetic Particles / Solar Radiation: GOES18 >10MeV proton flux was a little above normal background levels, but below the S1/Minor Radiation Storm threshold.

Four-Day Space Weather Forecast Summary

Solar Activity: Moderate activity is forecast, with further Moderate-class flares likely from the large region near centre disc. There remains a slight chance of Strong-flares from this region.

Solar Wind / Geomagnetic Activity: The recent Moderate-class flare produced an Earth-directed CME. Preliminary analysis suggests the CME could arrive at Earth on Day 3 (Friday).

Solar wind speeds are expected to remain slow on Day 1 (26 Aug) otherwise, before the arrival of the fast stream associated with CH90/+, likely on Day 2 (27 Aug). Wind speeds may increase to around 500 km/s, and potentially up to 550 km/s under the influence of the CME.

Geomagnetic activity is expected to remain Quiet (Kp 0–2) initially. However, conditions are likely to become Unsettled to Active (Kp 3–4) from Day 2 (27 August), with an increasing chance of G1/Minor Storm (Kp 5) intervals as the anticipated high-speed stream (HSS) from CH90/+ arrives.

The expected CME arrival on Day 3 (28 August) is then likely to maintain elevated geomagnetic activity, with a further chance of G1/Minor Storm intervals. Activity should begin to subside on Day 4, although Unsettled to Active (Kp 3–4) conditions may persist before gradually easing.

Energetic Particles / Solar Radiation: There is a generally increasing chance of solar radiation reaching above the S1/Minor radiation storm threshold through the period.