Space Weather Forecast Headline: Moderate-class flares likely. Chance of isolated G1-G2 Minor to Moderate Geomagnetic Storms Days 2-4 (27-29 Aug).

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Moderate, with a a single low Moderate class flare observed 26/0634 UTC from the complex sunspot region, now just west of the centre disc. Despite its relatively modest size, this is a relatively complicated region comprised of a number of small spots with multiple mixed magnetic polarities, and continues to show dynamical evolution. The other regions are all smaller and simpler, including a region now approaching the northwest limb, and relatively simple bipolar group in the northwest,  and a simple mature unipolar spot

At least two Coronal Mass Ejections (CMEs) have been assessed as being potentially on the Earth-Sun line, including one from a Moderate flare which was just before this period. This was followed by a weak eruption around 25/1300UTC in a similar vicinity to the same spot. While these were deflected east, glancing impacts are likely on days 3 (28 Aug), perhaps continuing into early day 4 (29 Aug). A third slower CME potentially followed from around 25/2100UTC, however this has an uncertain source, is faint in imagery and slow, leading to very low confidence. The Moderate-class flare flare on 26 Aug also likely produced a weak CME, however this has yet to be identified on available imagery.   

Solar Wind / Geomagnetic Activity: Solar winds, as measured at L1 by SOLAR-1, were indicative of the slow wind. Background solar wind speeds slowly declined from 340 km/s to just below 300km/s. Interplanetary Magnetic Field was weak with the north-south component also varying weakly. Geomagnetic activity was Quiet to Unsettled (Kp0-1). 

Energetic Particles / Solar Radiation: The count rate of energetic particles (high energy protons) remained a little above normal background, but below the S1/Minor Radiation Storm threshold and easing.

Four-Day Space Weather Forecast Summary

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

Solar Wind / Geomagnetic Activity: At least one CME arrival is likely to be observed on day 3 (28 Aug) from the eruptions on 25 Aug. Fast solar winds from a coronal hole are expected to be observed from early day 2 (27 Aug), with solar winds peaking around 500km/s. Geomagnetic activity will be mainly Quiet, but with spells of Unsettled to Active, with a likelihood of isolated G1 Minor Storms, with both the coronal hole and CME arrivals. There is a chance for isolated G2 intervals on day 3-4 (28-29). from any persistent CME influence. 

Energetic Particles / Solar Radiation: The count rate of energetic particles (high energy protons) is most likely to continue at Background, but given the history of enhancements from the complex centre-disc region, even when it was in an unfavourable location, then any similar events bring a chance for these rates to rise. This give a chance for an S1-S2 Minor to Moderate radiation storm, most likley on day 3-4 (28-29 Aug).