Report of Solar Geophysical Activity (RSGA)

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 108 Issued at 2200Z on 18 Apr 2013

IA.  Analysis of Solar Active Regions and Activity from 17/2100Z to
18/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C6 event observed at
18/1823Z from Region 1719 (N09W91). There are currently 5 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is likely to be low with a
slight chance for an M-class flare on day one (19 Apr) and likely to be
low on day two (20 Apr) and expected to be very low with a chance for a
C-class flares on day three (21 Apr).

IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic
field has been at quiet levels for the past 24 hours. Solar wind speed,
as measured by the ACE spacecraft, reached a peak speed of 359 km/s at
18/1408Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 126 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one, two, and three (19 Apr, 20 Apr, 21
Apr).

III.  Event probabilities 19 Apr-21 Apr
Class M    10/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           18 Apr 105
Predicted   19 Apr-21 Apr 095/090/090
90 Day Mean        18 Apr 111

V.  Geomagnetic A Indices
Observed Afr/Ap 17 Apr  002/003
Estimated Afr/Ap 18 Apr  002/002
Predicted Afr/Ap 19 Apr-21 Apr  006/005-005/005-004/005

VI.  Geomagnetic Activity Probabilities 19 Apr-21 Apr
A.  Middle Latitudes
Active                10/10/10
Minor Storm           01/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/15
Minor Storm           15/15/15
Major-severe storm    10/10/10