Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
176 FXXX12 KWNP 281231 DAYDIS :Product: Forecast Discussion :Issued: 2026 May 28 1230 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 (S16E16, Fko/beta-gamma) at 27/1216 UTC. There are ten numbered regions on the visible disk. Region 4452 (N09W35, Dai/beta) showed notable growth and new flux emergence, exhibiting a reversed polarity for its hemisphere. Regions 4445 (N07, L=163) and 4450 (N10, L=140) decayed to plage, though unassociated transitory pores were observed to in their vicinities. Regions 4453 (N11W76, Bxo/beta), 4454 (S15E48, Hrx/alpha), and 4455 (N15E65, Dao/beta) were numbered during the period, the later of which had rotated sufficiently onto the visible disk to verify a bipolar nature, so while some foreshortening effects are still present, the regions classification was updated to reflect this. All other regions continued either in slow decay or remained stable. A faint narrow CME first became visible in LASCO C2 at approximately 27/2300 UTC and CCOR1 at 28/0045 UTC. Data gaps in both disk and coronagraph imagery significantly complicate the analysis, so at the time of this writing, no on-disk source has been determined and while analysis suggests an Earth-directed component with potential for a minor glancing blow on 31 May, confidence in this analysis is low. 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 4455. 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 383 pfu observed at 27/1605 UTC. The greater than 10 MeV proton flux returned to 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 remain at background levels through 30 May. Solar Wind .24 hr Summary... Solar wind parameters reflected slightly elevated background conditions: The solar wind speed ranged from ~350 km/s to ~425 km/s, while the total magnetic field (Bt) generally averaged near 6 nT for the majority of the reporting period; at approximately 28/0250 UTC, Bt began gradually increasing, reaching a max of 10 nT at 28/1023 UTC. The north-south (Bz) component displayed high variability, oscillating between a maximum southward deflection of -8 nT and a positive orientation of +9 nT. The phi angle was largely in the negative (towards the Sun) sector, with several deviations to the positive sector throughout the period. .Forecast... Solar wind parameters are expected to remain mildly elevated 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 be at quiet 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.