Past Events
The solar activity was at very low levels since our last forecast on July 6. AR2766 which was present on July 6, decayed the next day and the Sun returned to its spotless condition for four days. Later on July 11, AR2766 became visible again at around west limb with 12 sunspots, yet the spots and AR decayed the next day on July 12. No significant CMEs or flares originated from AR2766 since it was a magnetically weak region. Two filament eruptions observed through SDO AIA 304 on July 8 at around 20.30 UTC and July 9 at around 01.00 UTC. The first eruption is observed at southern hemisphere around central meridian and the second one is at south western limb around the edge of the limb. Both of these filaments caused non Earth-directed CMEs with speeds below 350 km/s. The solar wind speed slowly decreased throughout the week from 500 km/s to 300 km/s. The maximum Kp was 2.
Within the last 24 hour solar activity was at very low levels. The Sun was a spotless disk without any sunspots and active regions. No significant flares or CMEs were observed. There are only two coronal holes at south and north poles. The solar wind speed had been decreasing since the last week and started to increase again by July 13 from 275 to 326 km/s due to the past northern coronal hole. The strength of southward IMF started to fluctuate around midnight between -8.81 and 5.44 nT. The minimum magnetopause standoff distance was 8 Re. The maximum Kp was 2. The geomagnetic indice Dst varied between -25 and -8 nT. AE was below 500 nT. The F10.7 radio flux was 68 sfu which is normal during solar minimum.
The solar activity is expected to remain at very low levels. ASSA flare model predicts the occurrence possibility of C, M and X class flares as, 9%, 1% and 0% respectively. The CME observed on July 9 is expected to arrive Earth with a glancing blow on July 14 according to ENLIL model. This might cause unsettlement in geomagnetic conditions. The solar wind speed is expected to slightly increase due to the past northern coronal holes for the rest of the day and tomorrow on July 14. Geomagnetic field might also be slightly disturbed due to the increased solar wind speed. All of the conditions are expected to return to their nominal conditions by July 15-16.
Forecaster: Ezgi Gülay
MSc. Student
Faculty of Aeronautics and Astronautics, ITU
Supervisor: Dr. Emine Ceren Kalafatoğlu Eyigüler