Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 12 April 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 102 Issued at 2200Z on 12 Apr 2013

IA. Analysis of Solar Active Regions and Activity from 11/2100Z to
12/2100Z: Solar activity has been at moderate levels for the past 24
hours. The largest solar event of the period was a M3 event observed at
12/2038Z from Region 1718 (N21W46). 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 (13 Apr, 14 Apr, 15 Apr).

IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z: 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 525 km/s at
12/0311Z. Total IMF reached 5 nT at 12/0713Z. The maximum southward
component of Bz reached -4 nT at 11/2125Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 65 pfu at 11/2120Z.
Electrons greater than 2 MeV at geosynchronous orbit reached a peak
level of 274 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to major storm levels on day one (13 Apr), unsettled to
major storm levels on day two (14 Apr) and quiet levels on day three (15
Apr). Protons have a chance of crossing threshold on day one (13 Apr)
and have a slight chance of crossing threshold on days two and three (14
Apr, 15 Apr).

III. Event probabilities 13 Apr-15 Apr
Class M 50/50/50
Class X 15/15/15
Proton 50/10/10
PCAF yellow

IV. Penticton 10.7 cm Flux
Observed 12 Apr 138
Predicted 13 Apr-15 Apr 135/130/120
90 Day Mean 12 Apr 113

V. Geomagnetic A Indices
Observed Afr/Ap 11 Apr 004/004
Estimated Afr/Ap 12 Apr 005/005
Predicted Afr/Ap 13 Apr-15 Apr 018/026-028/045-007/008

VI. Geomagnetic Activity Probabilities 13 Apr-15 Apr
A. Middle Latitudes
Active 30/30/15
Minor Storm 35/45/05
Major-severe storm 10/15/01
B. High Latitudes
Active 10/15/15
Minor Storm 20/25/20
Major-severe storm 60/35/20