Solar Activity

» 24 hr Summary: Solar activity remained at low levels with C-class flare activity. Region 4446 (S15W21, Cho/beta) produced a C4.8 flare at 30/1153 UTC, which was the largest event of the period. Region 4452 (N10W61, Dai/beta-gamma) exhibited decay primarily in its leading spots, but managed to maintain a mixed polarity magnetic configuration. Region 4455 (Dho/beta) gained additional spots, but lacked any significant flare activity. Region 4457 (S10W00, Cro/beta) rapidly emerged and was subsequently numbered. The remaining active regions remained relatively stable and quiet.

The halo CME, first observed by GOES CCOR-1 at approximately 30/0915 UTC, was assessed to have originated from the far side of the Sun. A faint and narrow CME associated with the aforementioned C4.8 flare event is undergoing modeling efforts as of the time of this writing. Any impacts to Earth are anticipated to be negligible.

» Forecast: Solar activity is expected to be at low to moderate levels through 02 Jun with a chance for isolated M-class flare activity.

Energetic Particle

» 24 hr Summary: The greater than 2 MeV electron flux at geosynchronous orbit was at low to moderate levels. The greater than 10 MeV proton flux at geosynchronous orbit remained at background levels.

» Forecast: The greater than 2 MeV electron flux is expected to remain at low to moderate levels through 31 May with a chance for high levels on 01 and 02 Jun. The greater than 10 MeV proton flux is expected to remain at background levels through 02 Jun.

Solar Wind

» 24 hr Summary: Solar wind parameters reflected negative polarity CH HSS influences. Total field increased to 10-11 nT. The Bz component of the IMF underwent a few sustained southward deflections reaching -7 to -10 nT. Solar wind speeds increased from just below 400 km/s to near 550 km/s by the end of the period.

» Forecast: Negative polarity CH HSS influences are expected to continue through 01 Jun with possible glancing influences from the slow eruptions that departed the Sun on 27 and 28 May. Ambient-like conditions are expected to return by the close of 02 Jun.

Geospace

» 24 hr Summary: The geomagnetic field was at quiet to active levels in response to negative polarity CH HSS influences.

» Forecast: Unsettled to active conditions, with a chance for isolated G1 (Minor) levels, are expected on 31 May due to negative polarity CH HSS effects. Chances for isolated G1 (Minor) storm periods increase on 31 May with any glancing influences from the aforementioned 27-28 May CMEs. Quiet to active levels are expected to continue into the early to mid portions of 01 Jun as negative polarity CH HSS effects wane with mostly quiet conditions prevailing on 02 Jun.


Prepared by:
The U.S. Dept. of Commerce, NOAA, SWPC