:Product: Forecast Discussion :Issued: 2025 May 20 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity reached low levels. Region 4087 (N16W21, Dso/beta) remains the largest region on the disk but has exhibited decay in the previous 24 hrs. Region 4091 (S13E02, Bxo/beta) is decaying fairly quickly with all other regions remaining stable. New Region 4093 (S06E76, Cso/beta) was numbered and has produced C-class activity. A new spotted region has rotated onto the visible disk at approximately N19E75. We await further observations before assigning a region number. At around 18/2100-19/0100 UTC, an approximately 25 degree long filament was observed lifting off the north-central quadrant of the visible disk. The bulk of the ejecta is expected to pass above Earth with a very weak glance possible on the 23 May. No other Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to be low, with a 35% chance for R1-R2 (Minor-Moderate) events, over 20-22 May. Probabilities increased slightly based on the flare potential of the active region near the NE limb. Energetic Particle .24 hr Summary... The coronal hole (CH) high speed stream (HSS) originating from the large positive polarity CH in the southern hemisphere is bringing an enhancement of electrons at geostationary orbit. The GOES-19 satellite observed a peak flux of 1,870 pfu at 19/1655 UTC in the greater than 2 MeV electron flux. There was a slight rise in the higher energetic proton channels as observed by ACE SIS, the most likely culprit was the X2.7 that occurred near the east limb on 14/0824 UTC. There was no rise in the greater than 10 MeV proton flux, it remained unaffected at background levels. .Forecast... With the continuing CH HSS, electrons are expected to reach high levels during the diurnal maxima through 22 May. With no complex active regions in the western hemisphere, protons are expected to remain at background level. Solar Wind .24 hr Summary... Solar wind parameters reflected ongoing HSS influence. The total field (Bt) remained around 5-9 nT with a variable north-south (Bz) component between +7/-5 nT. Wind speeds were steady near 450-500 km/s. The phi angle remained mostly in the positive (away from the Sun) orientation. .Forecast... Solar wind parameters will continue to see effects from the CH HSS through 22 May. Geospace .24 hr Summary... The geomagnetic field has been quiet to unsettled. .Forecast... Quiet to unsettled conditions will continue through 22 May as Earth remains in a geoeffective position with the CH HSS previously mentioned. Periodic active conditions remain possible during this time.