Here is this week’s space weather and geophysical report, issued 2016 Jul 18 0416 UTC.
Highlights of Solar and Geomagnetic Activity 11 – 17 July 2016
Solar activity was at very low levels from 11-14 July with only a few simple sunspot regions. Region 2565 (N05, L=175, class/area Cko/350 on 17 Jul) rotated onto the east limb on 11 July as a simple Hsx spot class with a simple alpha magnetic class. By late on 14 July, another spot group began to emerge behind Region 2565 and was numbered 2567 (N05, L=165, class/area Dhi/330 on 17 Jul). Region 2567 quickly grew to over 300 millionths in area and was initially classified as a beta-gamma-delta magnetic group before some magnetic simplification occurred on 16 July. The region was downgraded to a beta-gamma magnetic class for the remainder of the period. Region 2567 became the most active region during 15-17 July producing 13 C-class flares. However, the close proximity of the two regions, as well as an active inversion line between the two, resulted in several flares to be attributed to Region 2565 on 17 July. The first was a long duration C1/Sf flare at 17/0803 UTC which was responsible for two CMEs observed in SOHO/LASCO C2 imagery beginning at 17/1124 UTC and 17/1248 UTC. The first was a faint asymmetric halo CME while the second was directed mostly off the east limb. Initial WSA-Enlil model output of the events showed a slow transit with effects possible on 21 July. The largest flare of the period, however, was a C6 at 17/2335 UTC which also occurred on the inversion line and was subsequently attributed to Region 2565.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit reached high levels throughout the period with a maximum flux of 5,512 pfu observed at 17/1630 UTC.
Geomagnetic field activity ranged from quiet to G1 (Minor) storm levels. The majority of the period was under the influence of high speed solar wind streams from a large, positive polarity, polar connected coronal hole as well as an isolated, positive polarity coronal hole. Solar wind speeds reached highs around 550 km/s early on 11 July, 650 km/s late on 12 July, and 700 km/s early on 15 July before finally decreasing to around 440 km/s by the end of the period. Total field during the period only managed to reach a maximum of 9 nT at 12/0552 UTC. Prolonged periods of southward Bz reaching -8 nT on 12 July and -6 nT on 14 July resulted in periods of G1 (Minor) storm levels on 12 July and active periods on 14 July. The rest of the period was at quiet to unsettled levels with quiet conditions observed on 17 July.
Forecast of Solar and Geomagnetic Activity 18 July – 13 August 2016
Solar activity is expected to be at low levels with a chance for M-class (R1-R2, Minor-Moderate) flares from 18-24 July as Regions 2565 and 2567 transit across the visible disk. Very low levels are expected for 25 Juy-04 August. A return to low levels with a chance for M-class flaring is expected for 05-13 August with the return of Regions 2565 and 2567.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 18-19, 23-27 July, and again on 05-13 August due to recurrent CH HSS activity. Normal to moderate levels are expected for the remaining forecast period.
Geomagnetic field activity is expected to be at unsettled to active levels on 19-20, 22-24, 28, 30 July and on 03-08, 10-11 August with G1 (Minor) storm levels likely on 03-04 and 08 August due to recurrent CH HSS activity. A CME associated with the 17 July long-duration C1 flare is likely to arrive early on 21 July causing unsettled to active levels.
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