Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
495 FXXX12 KWNP 280031 DAYDIS :Product: Forecast Discussion :Issued: 2026 May 28 0030 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # Forecast Discussion # Solar Activity .24 hr Summary... Solar activity remained at low levels. The largest event of the period was a C3.4 flare originating from Region 4446 (S16E30, Fko/beta-gamma). There are nine numbered regions on the visible disk. Region 4452 (N09W21, Cai/beta) showed notable growth and new flux emergence. Region 4450 (N10, L=140) decayed to plage, though unassociated transitory pores were observed to its east and west. Region 4443 (S17W67, Hsx/alpha) decayed into a unipolar spot as it approached the west limb following the loss of its leading components. Regions 4453 (N11W63, Bxo/beta), 4454 (S15E61, Axx/alpha), and 4455 (N14E78, Hax/alpha) were numbered during the period. Far-side satellite imagery from Solar Orbiter indicates that Region 4455 is likely a large bipolar group with its trailing opposite-polarity spots still located behind the east limb and was numbered proactively due to its flaring potential. All other regions continued either in slow decay or remained stable. A faint, potentially partial-halo CME first seen in LASCO C2 imagery around 26/2230 UTC and subsequently in GOES/CCOR1 was analyzed. No obvious on-disk source exists. Modeling suggests a possible glancing blow at Earth on 31 May. Additionally, narrow eruptions associated with flaring from newly numbered Region 4444 were seen in SUVI imagery around 0200 UTC and 1330 UTC, but these features are well northward of the ecliptic plane with no Earth-directed components. No other Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to be at low to moderate levels through 30 May. There remains a chance for isolated M-class flares (R1-R2/Minor-Moderate) driven by the eruptive potential of the southeast sunspot groups and newly numbered Region 4454. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux at geosynchronous orbit was at low to moderate levels, with a peak flux of 403 pfu observed at 27/1155 UTC. The greater than 10 MeV proton flux remained elevated following the S1 (Minor) solar radiation storm on 26 May, continuing a slow, gradual decay back towards background after beginning the period near 1 pfu. Higher energy channels (>50 MeV) remained at background levels. .Forecast... The greater than 2 MeV electron flux is expected to remain at low to moderate levels through 30 May, as approaching high-speed stream enhancements are not expected to be sufficient to raise flux levels. The greater than 10 MeV proton flux is anticipated to continue its gradual decline toward background levels on 2830 May. Solar Wind .24 hr Summary... Solar wind parameters remained slightly elevated and possibly indicative of weak negative polarity coronal hole high-speed stream (-CH HSS) influences. Total magnetic field (Bt) was fairly steady, averaging near 6.0 nT. The north-south (Bz) component displayed high variability, oscillating between a maximum southward deflection of -7.0 nT and a positive orientation of +6 nT. Solar wind speeds varied modestly between 350 and 425 km/s. The phi angle was predominantly in the negative (towards the Sun) sector, though minor deviations were observed later in the period. .Forecast... Solar wind parameters are expected to remain mildly enhanced due to weak -CH HSS influences through 29 May. A return toward near-background, nominal conditions is anticipated by 30 May. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels throughout the reporting period. .Forecast... The geomagnetic field is anticipated to increase to unsettled levels, with a chance for isolated active periods, on 28 May due to continued CH HSS influences. Unsettled conditions are expected to persist on 29 May before returning to mostly quiet levels early on 30 May as these effects subside.