Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 260 Issued at 2200Z on 16 Sep 2012
IA. Analysis of Solar Active Regions and Activity from 15/2100Z
to 16/2100Z: Solar activity was very low. New Region 1573 (N17E62 -
Axx/alpha) produced occasional B-class flares as it rotated into
view. Region 1566 (N23W89 - Hrx/alpha) produced a B-class flare as
it approached the west limb. Region 1569 (S12W13 - Cso/beta) showed
gradual spot and penumbral decay in its intermediate and trailer
portions. New Region 1574 (S25W15 - Bxo/beta), a small
reverse-polarity group, was also numbered. No Earth-directed CME activity
occurred during the period.
IB. Solar Activity Forecast: Solar activity is expected to be very
low through the period (17 - 19 September) with a chance for a
C-class flare.
IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z:
Geomagnetic field activity was at quiet to unsettled levels. An
increase to unsettled levels occurred late in the period associated
with the onset of a solar sector boundary crossing (SSBC).
Intermittent periods of weakly-southward IMF Bz along with minor
increases in solar wind speeds and IMF Bt were associated with the
SSBC.
IIB. Geophysical Activity Forecast: Geomagnetic field activity is
expected to remain at quiet to unsettled levels on day 1 (17
September) due to minor changes in the solar wind. A decrease to
quiet levels is expected on day 2 (18 September). Activity is
expected to increase to quiet to unsettled levels on day 3 (19
September), with a slight chance for active levels, as a coronal
hole high-speed stream begins to disturb the field.