=================================== Weekly Space Weather Highlights =================================== Highlights of Solar and Geomagnetic Activity 16 - 22 October 2017 Solar activity was at very low levels with the exception of 20 Oct when an M1 flare was observed on the southeastern limb. The M1 flare occurred at 20/2328 UTC from Region 2685 (S09, L=131, class/area Hax/070 on 22 Oct) with an associated Type II (344 km/s) radio sweep and a coronal mass ejection (CME) off the east limb first observed at 21/0012 UTC in SOHO/LASCO C2 imagery. By the time Region 2685 rotated fully into view, it was a simple alpha spot group and has been quiet since the M-class event. No Earth-directed CMEs were observed during the period. No proton events were observed at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit reached moderate levels on 20 and 22 Oct with high levels on 16, 19 and 21 Oct. Very high levels were observed on 17-18 Oct. The largest flux of the period was 56,839 pfu observed at 17/1535 UTC. Geomagnetic field activity ranged from quiet to active levels. The period began under the weakening influence of a polar connected, positive polarity coronal hole high speed stream (CH HSS). Solar wind speed declined from approximately 550 km/s early in the period to near 350 km/s by late on 18 Oct. Total field was at 5 nT and below during this timeframe. The geomagnetic field responded with quiet to unsettled levels on 16 Oct and quiet levels on 17-18 Oct. By 19 Oct, a weak connection with the positive polarity polar CH was observed resulting in a brief increase of solar wind speed to near 470 km/s and total field at 10 nT. Solar wind speed again decreased to nominal levels by early on 21 Oct. The geomagnetic field responded with quiet to unsettled levels on 19 Oct and quiet to active levels on 20 Oct. A solar sector boundary crossing into a negative sector was observed at 21/0730 UTC followed by a weak enhancement from a negative polarity CH HSS. Solar wind speed increased to near 490 km/s late on 21 Oct with total field increasing to near 10 nT. By late on 22 Oct, solar wind parameters had once again decreased to nominal levels. The geomagnetic field responded with quiet to unsettled levels on 21-22 Oct. Forecast of Solar and Geomagnetic Activity 23 October - 18 November 2017 Solar activity is expected to be at very low to low levels with a slight chance for M-class flares (R1-Minor) on 23-06 Nov due to potential flare activity from Region 2685 and the return of old Region 2683 (N13, L=111) to the visible disk. From 07-18 Nov, only very low levels are expected. No proton events are expected at geosynchronous orbit. The greater than 2 MeV electron flux at geosynchronous orbit is likely to be at high levels on 25-26 Oct, 28 Oct-01 Nov, 08-10 Nov, 12 Nov, 15 Nov and 17 Nov with very high levels on 27 Oct, 11 Nov and13-14 Nov due to CH HSS influence. Geomagnetic field activity is expected to be unsettled to active levels on 24-29 Oct, 01-02 Nov, 07-11 Nov and 15-17 Nov with G1 (Minor) storm levels likely on 24-26 Oct, 07-11 Nov and G2 (Moderate) levels likely on 25-26 Oct and 09-10 Nov due to recurrent CH HSS effects.