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 five sunspot regions on the visible disc. All regions are small or moderately sized but magnetically simple and stable.

A further fast coronal mass ejection was observed in imagery late morning UTC on 14 Sep, associated with a filament eruption in the southwest. This has been analysed to possibly give glancing impacts late 16 Sep. 

 Solar Wind / Geomagnetic Activity: Solar winds indicated weak fast wind effects with an embedded weak coronal mass ejection at 14/0225 UTC. Solar wind speeds have been background at 280-390km/s. The interplanetary magnetic field started weak, then gradually rose through the period becoming mostly moderate after 14/1100 UTC, peaking at 14/1800 UTC. The north-south component, Bz, followed a similar trend, and was variable, with the most significant period of moderately negative between 14/1350-1510 UTC. Geomagnetic activity was Quiet to Active (Kp 1-4). 

Energetic Particles / Solar Radiation: No solar radiation storms were observed, though proton flux rose from background to mostly Moderate levels, peaking at 14/1520 UTC.

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 ongoing weak enhancement is likely attributed to the southern coronal hole, but may have further influence through day 1 (15 Sep). The second enhancement is expected to be more considerable, with solar winds likely becoming Elevated to Strong 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 Quiet to Unsettled (Kp0-3) initially. There is then a chance of Active to G1/Minor storms (Kp4-5) at times day 1 (15 Sep) due to multiple fast wind effects, with a slight chance of G2/Moderate (Kp6) storm intervals late in the period should the 13 Sep coronal mass ejection arrive early. On day 2, (16 Sep) combined fast winds and possible coronal mass ejection 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 fast wind effects and perhaps residual coronal mass ejection 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 fast winds begin to wane.

Energetic Particles / Solar Radiation: Proton flux is at Moderate levels, due to 13 Sep coronal mass ejection effects, though below the S1/Minor solar radiation storm level. There is a Chance of rising above the S1 threshold day 1 (15 Sep) due to possible effects from the 14 Sep coronal mass ejection, though confidence is low.