Weekly Highlights of Solar and Geomagnetic Activity, 17 - 23 October 2016
 

:Product: Weekly Highlights and Forecasts
:Issued: 2016 Oct 24 0702 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/weekly.html
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
17 - 23 October 2016

Solar activity was very low to low with a single C-class flare
observed on 17 Oct. At 17/0038 UTC, a C4 flare was observed from
Region 2599 (S15, L=144, class/area Cko/460 on 05 Oct) which had
rotated around the southwest limb on 15 Oct. A nine degree long
filament, centered near N26W02, was observed erupting in SDO/AIA 304
and GONG imagery at about 20/1300 UTC. A slow-moving, faint CME was
observed in LASCO C2 imagery with possible effects observed on 23
October.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit ranged
from normal to very high levels. On 18 Oct very high levels were
observed, with a peak level of 52,137 pfu. High levels were observed
on 17 Oct and 19-22 Oct. Normal to high levels were observed on 23
Oct.

Geomagnetic field activity during the reporting period ranged from
quiet to active levels. Quiet to active conditions were observed on
17 Oct and tapered into quiet to unsettled levels through 19 Oct due
to the waning effects of a CH HSS. Quiet conditions were observed
from 20-22 Oct under an ambient solar wind regime. Quiet to
unsettled conditions were noted 23-24 Oct due to a SSBC and initial
CH HSS effects.

The solar wind environment was above background levels on 17 Oct
under the influence of a CH HSS with wind speeds between 700-800
km/s. Wind speeds gradually tapered to background conditions on
18-19 Oct. Winds increased again to around 450 km/s and minor
enhancements to total field were observed on 23 Oct due to a SSBC
and weak CH HSS effects.

Forecast of Solar and Geomagnetic Activity
24 October - 19 November 2016

Solar activity is expected to be very low with a chance for C-class
activity throughout the outlook period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 24-26 Oct, 30 Oct-6 Nov, and 12-19
Nov and very high levels 27-29 Oct. Normal to moderate levels are
expected 7-11 Nov. Enhancement in the 2 MeV electron flux is due to
the anticipation of multiple, recurrent CH HSSs.

Geomagnetic field activity is likely to reach major storm levels
(G2-Moderate) on 24-26 Oct, and minor storm levels (G1-Minor) on
27-29 Oct, due to the effects of a positive polarity CH HSS. Active
conditions are likely to linger through 01 Nov as effects of the CH
HSS wane. Thereafter, conditions are expected to be predominately
quiet with isolated unsettled periods through 10 Nov. Active
conditions are likely on 12 Nov, increasing to G1 storm conditions
on 13 Nov, under the influence of a negative polarity CH HSS.
Conditions are likely to decrease to unsettled from 14-15 Nov as CH
HSS effects wane. Quiet conditions are then expected on 16-18 Nov,
increasing to unsettled by 19 Nov with the onset of another positive
polarity CH HSS.