Space Weather Forecast Headline: Chance of G1/Minor and slight chance of G2/Moderate days 1 and 3. Likely G1/Minor with chance G2/Moderate and slight chance of G3/Strong day 2. Chance of S1/Minor day 1.

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Solar activity has been Very Low, with peak flare at 14/1433 UTC from near the northwest limb. There are four sunspot regions on the visible disc. All of which are small or magnetically simple. 

There were no Earth directed CMEs (coronal mass ejections) observed during this period. 

 Solar Wind / Geomagnetic Activity: Solar winds indicated weak fast wind and possible CME effects, until later in the period, at which point a stronger connection to a CH HSS may have occurred. Solar wind speeds were mainly background between 300-400km/s until around 15/0914UTC, at which point they became slightly elevated. Speeds then showed a sharp increase towards the end of the period with a peak of 814km/s at 15/1133 UTC. The interplanetary magnetic field started weak, then gradually rose through the period becoming mostly moderate after 14/1100 UTC, but did peak at strong levels of at 15/0953 UTC. The north-south component, Bz, was Moderate and variable, but was positive from 14/2230UTC. Geomagnetic activity was Quiet to Active (Kp 1-4). 

Energetic Particles / Solar Radiation: Proton flux was initially above the S1/Minor threshold, but fell below the S1 threshold from 15/0405UTC. 

Four-Day Space Weather Forecast Summary

Solar Activity: Solar activity is expected to remain Low or Very Low with only a slight chance of reaching Moderate levels should any isolated Moderate-class flares occur.

Solar Wind / Geomagnetic Activity: Two coronal mass ejections feature in the forecast, both filament eruption from the southwest quadrant, one from 13 Sep and another from 14 Sep. Both bring a chance of arrival early and late on 16 Sep respectively, with glancing impacts most likely. 

There are two coronal holes that feature in the forecast, the first is in the southwest followed by one in the northwest. The weak enhancement seen for the majority of the past 24 hours is attributed to the southern coronal hole. The second enhancement is likely now be being seen at Earth, with speeds showing a sharp to strong levels in the last hour. This enhancement is expected to be more considerable. Strong speeds may now be observed from later day 1 until day 3 (15-17 Sep), before gradually easing back to Slightly Elevated levels later day 3 or on day 4 (17-18 Sep).

Geomagnetic activity is expected to be Unsettled to Active (Kp3-4), with a chance of G1/Minor storms (Kp5) at times day 1 (15 Sep) due to multiple CH HSS effects, with a slight chance of G2/Moderate (Kp6) storm intervals late in the period should the 13 Sep CME arrive early. On day 2, (16 Sep) combined CH HSS and possible CME glancing blows early and late, bringing likely G1/Minor (Kp5), Chance of G2/Moderate (Kp6) and slight chance of G3/Strong (Kp7) storming. Day 3 (17 Sep) will see lingering HSS effects and perhaps residual CME effects with a chance of G1/Minor (Kp5) and a slight chance of isolated G2/Moderate (Kp6) intervals. Day 4 should return to largely Quiet to Unsettled (Kp0-3) as HSS influences wane.

Energetic Particles / Solar Radiation: Proton flux has returned to background levels following earlier enhancement. Further enhancements are considered unlikely due to the lack of complexity on the disc, but there is a slight chance of seeing some slight proton enhancement ahead of the possible, glancing CMEs expected on the 16 September.