Report of Solar Geophysical Activity (RSGA)


Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 101 Issued at 2200Z on 11 Apr 2013

IA.  Analysis of Solar Active Regions and Activity from 10/2100Z to
11/2100Z: Solar activity has been at high levels for the past 24 hours.
The largest solar event of the period was a M6 event observed at
11/0716Z from Region 1719 (N10W00). There are currently 6 numbered
sunspot regions on the disk.
IB.  Solar Activity Forecast: Solar activity is expected to be low with
a chance for M-class flares and a slight chance for an X-class flare on
days one, two, and three (12 Apr, 13 Apr, 14 Apr).

IIA.  Geophysical Activity Summary 10/2100Z to 11/2100Z: 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 507 km/s at
11/1243Z. Total IMF reached 7 nT at 11/0712Z. The maximum southward
component of Bz reached -4 nT at 11/0916Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 114 pfu at 11/1645Z.
Protons greater than 100 MeV at geosynchronous orbit reached a peak
level of 2 pfu at 11/1400Z. Electrons greater than 2 MeV at
geosynchronous orbit reached a peak level of 385 pfu.
IIB.  Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on day one (12 Apr), quiet to major storm levels
on day two (13 Apr) and unsettled to major storm levels on day three (14
Apr). Protons are expected to cross threshold on day one (12 Apr), have
a chance of crossing threshold on day two (13 Apr) and have a slight
chance of crossing threshold on day three (14 Apr).

III.  Event probabilities 12 Apr-14 Apr
Class M    50/50/50
Class X    15/15/15
Proton     99/30/10
PCAF       red

IV.  Penticton 10.7 cm Flux
Observed           11 Apr 137
Predicted   12 Apr-14 Apr 138/135/130
90 Day Mean        11 Apr 113

V.  Geomagnetic A Indices
Observed Afr/Ap 10 Apr  005/004
Estimated Afr/Ap 11 Apr  004/005
Predicted Afr/Ap 12 Apr-14 Apr  006/005-018/026-028/045

VI.  Geomagnetic Activity Probabilities 12 Apr-14 Apr
A.  Middle Latitudes
Active                10/30/30
Minor Storm           01/35/45
Major-severe storm    01/10/15
B.  High Latitudes
Active                15/10/15
Minor Storm           15/20/25
Major-severe storm    10/60/35

NOAA Space Weather Scale descriptions can be found at

www.sec.noaa.gov/NOAAscales