Solar activity remained at low levels. A C2 flare from west of Region 2335 (S14W85, Bxo/beta) at 12/0302 UTC was accompanied by an eruption visible in LASCO C2 coronagraph imagery beginning at 12/0248 UTC, and associated with a proton enhancement observed shortly after. Region 2339 (N14W19, Fkc/beta-gamma) remained the largest of the 10 spotted regions on the visible disk. There was no significant development of any of the regions. The location of the CME described above makes a geoeffective event unlikely. Analysis and modeling of the CME support the west limb event heading upstream of Earth with no significant impacts expected. .Forecast... Solar activity is expected to be low with a chance for M-class (R1-R2/Minor-Moderate) flare activity over the next three days (13-15 May) with Region 2339 being the most likely source.Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux at geosynchronous orbit was at normal levels. The greater than 10 MeV proton flux at geosynchronous orbit began at background levels but rose after the C2 flare at 12/0302 UTC mentioned above. Flux at GOES reached a peak of 6 pfu at 12/0720. Upstream at the ACE spacecraft, a maximum of 8 pfu was recorded by the SIS instrument at 12/0855 UTC. The uptick in proton flux prompted a warning at 12/0627 UTC which was later canceled. .Forecast... The greater than 2 MeV electron flux at geosynchronous orbit is expected to persist at normal levels over the next three days (13-15 May). The 10 MeV proton flux is expected to remain below S1 (Minor) thresholds while decreasing back to background levels as the period progresses. Solar Wind .24 hr Summary... Solar wind speed at the ACE spacecraft saw signatures suggesting the onset of the recurrent negative polarity coronal hole high speed stream (CH HSS) during the period. Wind speeds remained low through the majority of the day between around 340 km/s to around 370 km/s. After 12/1700 UTC the winds began a steady rise in velocity to above 500 km/s, eventually seeing a a peak of 605 km/s. Bt was enhanced above 5 nT through most of the day, reaching a peak of 17 nT, while Bz saw a maximum southward deflection of -16 nT near the end of the period. Temperature has also seen a positive trend after 12/0400 UTC and continues to increase. .Forecast... The solar wind environment at the ACE spacecraft is expected to continue to see enhancements from the CH HSS over the next three days. Wind speeds are expected to continue to increase until early on day one (13 May) and slowly decline through day three (15 May).Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels. .Forecast... The geomagnetic field is expected to be at unsettled to active levels with minor (G1-Minor) storming conditions likely on day one (13 May) with the onset of a CH HSS. On day two through three (14 - 15 May), the high speed stream is expected to taper off, bringing geomagnetic conditions below minor (G1-Minor) thresholds.
Analysis of Solar Active Regions and Activity from 11/2100Z to 12/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C3 event observed at 12/1151Z from Region 2339 (N14W19). There are currently 10 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (13 May, 14 May, 15 May). IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 455 km/s at 12/1850Z. Total IMF reached 15 nT at 12/0649Z. The maximum southward component of Bz reached -9 nT at 12/1459Z. Protons greater than 10 MeV at geosynchronous orbit reached a peak level of 6 pfu at 12/0730Z. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (13 May), quiet to unsettled levels on day two (14 May) and quiet levels on day three (15 May). III. Event probabilities 13 May-15 May Class M 30/30/30 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 12 May 163 Predicted 13 May-15 May 160/155/150 90 Day Mean 12 May 127 V. Geomagnetic A Indices Observed Afr/Ap 11 May 015/021 Estimated Afr/Ap 12 May 015/019 Predicted Afr/Ap 13 May-15 May 019/025-011/012-007/008 VI. Geomagnetic Activity Probabilities 13 May-15 May A. Middle Latitudes Active 40/35/20 Minor Storm 25/15/05 Major-severe storm 05/01/01 B. High Latitudes Active 10/10/15 Minor Storm 25/30/25 Major-severe storm 60/45/25
