Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 24 April 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 114 Issued at 2200Z on 24 Apr 2013

IA. Analysis of Solar Active Regions and Activity from 23/2100Z to
24/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C2 event observed at
23/2325Z from Region 1726 (N13W49). There are currently 5 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 (25 Apr, 26 Apr, 27 Apr).

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic
field has been at quiet to active levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
483 km/s at 24/1927Z. Total IMF reached 23 nT at 24/0955Z. The maximum
southward component of Bz reached -18 nT at 24/0927Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to minor storm levels on day one (25 Apr), quiet to
active levels on day two (26 Apr) and quiet levels on day three (27
Apr). Protons have a slight chance of crossing threshold on days one,
two, and three (25 Apr, 26 Apr, 27 Apr).

III. Event probabilities 25 Apr-27 Apr
Class M 40/40/40
Class X 15/15/15
Proton 15/15/15
PCAF green

IV. Penticton 10.7 cm Flux
Observed 24 Apr 115
Predicted 25 Apr-27 Apr 115/115/115
90 Day Mean 24 Apr 111

V. Geomagnetic A Indices
Observed Afr/Ap 23 Apr 006/006
Estimated Afr/Ap 24 Apr 012/017
Predicted Afr/Ap 25 Apr-27 Apr 016/018-011/012-006/005

VI. Geomagnetic Activity Probabilities 25 Apr-27 Apr
A. Middle Latitudes
Active 25/15/10
Minor Storm 10/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/25/15
Major-severe storm 35/25/10