Space Weather Forecast Headline: Chance of G1/Minor Geomagnetic storm intervals day 1 (20 May). Slight chance of isolated R1/Minor Radio Blackouts throughout.

Analysis of Space Weather Activity over past 24 hours

Solar Activity: Solar Activity was Low with only Common-class flares observed.

There are currently five sunspot regions on the visible disc. The region in the northwest remains the largest and most active region, dominated by a substantial positive-polarity leading spot and appearing generally stable at present. A region near north-central disc exhibited some development, however growth has stalled with the trailer spot splitting. The remaining regions across the northeast and southeast quadrants are comparatively small and are either stable or gradually decaying.

There were no Earth-directed Coronal Mass Ejections (CME) observed in the past 24hrs.

Solar Wind / Geomagnetic Activity: Solar wind parameters were indicative of a combination of a waning coronal hole fast wind and a glancing CME arrival (which left the Sun on 16 May). Solar winds have been mostly Elevated, between 500-550km/s due to waning fast wind. However, a weak CME arrived at 19/0630 UTC, with solar winds briefly reaching Strong levels, peaking at 620km/s at 19/0658 UTC, before reducing back to the current Elevated levels. The Interplanetary Magnetic Field was Weak to Moderate. The north-south component became more variable and mostly negative (southward). The resulting geomagnetic activity was Quiet to Active (Kp1-4).

Energetic Particles / Solar Radiation: GOES18 high energy (>10 MeV) proton flux was at or near background, with no Solar Radiation Storms observed. 

Four-Day Space Weather Forecast Summary

Solar Activity: Low solar activity is expected to continue, though there remains a slight chance of isolated M-class flares.

Solar Wind / Geomagnetic Activity: Solar wind speeds are currently at Elevated levels. However, solar winds may briefly reach Strong levels on Day 1 (20 May) as a second glancing CME is likely to arrive at Earth, although this aspect of the forecast is low confidence. Thereafter, a gradual declining trend is anticipated over the following days, with solar wind speeds potentially easing to Slightly Elevated levels by Day 2 (21 May).

Geomagnetic activity is expected to remain largely at Quiet to Active levels (Kp1–4). However, there is a chance of G1/Minor Storm conditions (Kp5), along with a slight chance of isolated G2/Moderate Storm intervals (Kp6) into Day 1 (20 May), driven by the combined effects of the coronal hole high-speed stream and a possible weak glancing impact from a second CME.

Energetic Particles / Solar Radiation: GOES18 high energy (>10 MeV) proton flux is expected to remain at Background levels, with no solar radiation storms expected.