:Product: Weekly Highlights and Forecasts
:Issued: 2016 Dec 19 0057 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
12 - 18 December 2016

Solar activity was at background levels through the period.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 12-17 December and moderate levels on 18 December. A
maximum flux of 10,187 pfu was observed at 14/1610 UTC.

Geomagnetic field activity was at quiet to unsettled levels during
the period. The period began under the waning influence of a
negative polarity CH HSS with unsettled conditions early on 12
December. The remainder of the 12th through late on 17 December saw
quiet conditions. During this time, solar wind speeds slowly
decreased from about 550 km/s to near 350 km/s. Bt was less than 5
nT while the Bz component varied generally between +5 nT to -4 nT.
Phi angle was in a mostly negative orientation.

By midday on 17 December, winds speeds indicated a general increase
to about 500 km/s while Bt increased to about 10 nT and Bz showed
rotation from +6 nT to -7 nT. Phi angle rotated to a mostly positive
orientation. This increase in wind parameters signaled the arrival
of a co-rotating interaction region ahead of a weak, positive
polarity CH HSS. The geomagnetic field reacted with quiet to
unsettled levels.

Forecast of Solar and Geomagnetic Activity
19 December - 14 January 2017

Solar activity is expected to be at very low levels with a slight
chance for C-class flare 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 be at normal to moderate levels on 19 December and
moderate to high levels for the remainder of the outlook period (20
Dec - 14 Jan).

Geomagnetic field activity is expected to be at unsettled to active
levels on 19-25 December, 03-07 January and again on 14 January,
with minor storm (G1-Minor) conditions likely on 21-22 December and
04-05 January; all due to recurrent CH HSSs. Mostly quiet conditions
are expected for the remainder of the outlook period.