Space Weather Forecast Headline: Occasional Minor radio blackouts (R1) expected. Rising likelihood of Minor or Moderate geomagnetic storms G1/G2 from midweek UTC.

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Activity remained Moderate, with a peak Moderate-class flare observed at 27/0645UTC from a moderately sized sunspot region located in the northeast quadrant. 

There are currently seven sunspot regions on the Earth-facing side. Of these, the northernmost three regions are the most complex and dynamic. The sunspot region in the northwest continued to show a slight decay across the group in terms of its penumbral area, as well as a more open character developing, although there remains magnetic complexity within its central portion, with two delta spots. The moderately sized sunspot region in the east, with a large main central penumbral group of spots also containing at least two delta spots. Other regions were less-changed and simpler.

A moderate-class flare observed late on 26 Apr was associated with a radio burst that would typically be linked to an associated Coronal Mass Ejection (CME). This CME is not visible on available imagery or else the CME signature is 'polluted' by a similarly-timed event from over the western solar horizon. However, a very faint CME is just about visible in STEREO-A imagery, which has been analysed and gives a likely arrival at Earth late on Day 3 (30 Apr) or Day 4 (01 May), which would potentially be coincident with the fast wind from a coronal hole. 

Solar Wind / Geomagnetic Activity: The solar wind speed observed showed hesitant connection to a modest, positive polarity coronal hole. The solar wind speed has been at mostly Slightly Elevated  levels, averaging around 450km/s.. The magnetic field was weak. The all-important north-south component was also weak. 

The net result of the above solar wind measures was Quiet to Unsettled (Kp1-3) geomagnetic activity. 

Energetic Particles / Solar Radiation: No solar radiation storms were observed, nor even slight enhancements to proton counts in the near-Earth environment.

Four-Day Space Weather Forecast Summary

Solar Activity: Moderate solar activity is expected to continue at first, with occasional Moderate‑class flares and a slight chance of isolated Strong‑class flares. This flare risk expected to relax slightly through the period as confidence in the current spate of activity reduces. 

Solar Wind / Geomagnetic Activity: The aforementioned Moderate-class flare late on 26 Apr may have produced a CME, although there isn't much evidence in coronagraph imagery. However, there appears to be a faint CME visible in STEREO-A, which has been analysed. This gives a provisional arrival at Earth either late Day 3 or Day 4 (30 Apr - 01 May). This aspect of the forecast is very low confidence. No other CMEs feature in the forecast.

Mainly Quiet geomagnetic activity should precede the fast wind due around midweek UTC, however this will rise to an eventual Likely G1, with a Slight Chance of G2 on Days 2-4 (29 Apr - 01 May), which may coincide with a possible CME arrival either on the 30 Apr or 01 May, however this aspect is very low confidence.

Energetic Particles / Solar Radiation: There is a daily slight chance of Minor Solar Radiation Storms (S1). This risk is held constant, with a decreasing component from a region now on the far side of the Sun, but an increasing and compensatory component from the largest region on the Earth-facing side.