Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 13 April 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 103 Issued at 2200Z on 13 Apr 2013

IA. Analysis of Solar Active Regions and Activity from 12/2100Z to
13/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C1 event observed at
13/0334Z from Region 1718 (N21W58). There are currently 7 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 and two (14 Apr, 15 Apr) and expected to be low with a chance
for M-class flares on day three (16 Apr).

IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z: 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 501 km/s at
12/2336Z. Total IMF reached 5 nT at 12/2240Z. The maximum southward
component of Bz reached -3 nT at 13/0036Z. Protons greater than 10 MeV
at geosynchronous orbit reached a peak level of 10 pfu at 12/2205Z.
Electrons greater than 2 MeV at geosynchronous orbit reached a peak
level of 268 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to major storm levels on day one (14 Apr) and quiet
levels on days two and three (15 Apr, 16 Apr). Protons greater than 10
Mev have a chance of crossing threshold on day one (14 Apr) and have a
slight chance of crossing threshold on day two (15 Apr).

III. Event probabilities 14 Apr-16 Apr
Class M 40/40/30
Class X 10/10/05
Proton 30/10/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 13 Apr 125
Predicted 14 Apr-16 Apr 120/120/115
90 Day Mean 13 Apr 112

V. Geomagnetic A Indices
Observed Afr/Ap 12 Apr 004/004
Estimated Afr/Ap 13 Apr 010/012
Predicted Afr/Ap 14 Apr-16 Apr 028/045-007/008-006/005

VI. Geomagnetic Activity Probabilities 14 Apr-16 Apr
A. Middle Latitudes
Active 30/15/10
Minor Storm 45/05/01
Major-severe storm 15/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/20/20
Major-severe storm 35/20/10