Solar Activity

» 24 hr Summary: Solar activity was low. Region 4079 (N08W81, Cki/beta-gamma) produced most of the C-class flare activity this period, including an impulsive C5.5 flare at 10/1621 UTC. The region underwent slight decay as it approached the W limb. Decay was also observed among Regions 4081 (N07W50, Cao/beta), 4082 (S10W21, Hsx/alpha) and 4084 (S21E34, Hsx/alpha). New Region 4085 (N02E24, Bxo/beta) was numbered. No Earth-directed CMEs were detected in available imagery.

» Forecast: Solar activity is expected to be low on 11-13 May. However, there is a chance for M-class flares (R1/R2 -Minor/Moderate radio blackouts) on 11 May as Region 4079 completes its transit beyond the W limb.

Energetic Particles

» 24 hr Summary: The greater than 2 MeV electron flux reached moderate levels with a peak flux of 819 pfu observed at 10/1450 UTC. The greater than 10 MeV proton flux was steady at background levels throughout the period.

» Forecast: The greater than 2 MeV electron flux is likely to reach normal to moderate levels on 11-13 May. The greater than 10 MeV proton flux is expected to persist at background levels through 13 May.

Solar Wind

» 24 hr Summary: The solar wind environment remained mildly enhanced this period due to negative polarity CH HSS influences. Total IMF strength reached 9 nT and the Bz component varied between +/-6 nT. Solar wind speeds increased from a low of around 400 km/s to a brief peak of 550 km/s at 10/0707 UTC, then gradually declined to about 450 km/s by the end of the period. The phi angle was predominately negative throughout the period.

» Forecast: Slightly enhanced solar wind conditions are expected to prevail over 11 May, with negative polarity CH HSS influences expected to continue. Positive polarity CH HSS influences are expected to commence on 12 May and continue through 13 May.

Geospace

» 24 hr Summary: The geomagnetic field reached active levels early in response to negative polarity CH HSS influences. Mostly quiet levels were observed through periods end.

» Forecast: The geomagnetic field is likely to reach isolated active levels on 11 May due to continued negative polarity CH HSS influences. Quiet to unsettled conditions are expected to prevail early on 12 May with the transition between the negative polarity HSS and a positive polarity HSS. Conditions are likely to reach active levels again on 13 May as the positive polarity HSS settles into a geoeffective position.


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