Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 April 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 117 Issued at 2200Z on 27 Apr 2013

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to
27/2100Z: Solar activity has been at low levels for the past 24 hours.
The largest solar event of the period was a C5 event observed at
26/2225Z from Region 1726 (N13W93). 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 on days one, two, and three (28 Apr, 29 Apr,
30 Apr).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed started the period near 600 km/s and slowly decreased to near
490 km/s by the end of the period. Total IMF reached 5 nT at 26/2141Z.
The maximum southward component of Bz reached -3 nT at 26/2300Z.
Electrons greater than 2 MeV at geosynchronous orbit reached a peak
level of 2922 pfu.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet levels on days one, two, and three (28 Apr, 29 Apr, 30
Apr).

III. Event probabilities 28 Apr-30 Apr
Class M 25/25/25
Class X 05/05/05
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Apr 127
Predicted 28 Apr-30 Apr 125/125/125
90 Day Mean 27 Apr 112

V. Geomagnetic A Indices
Observed Afr/Ap 26 Apr 018/021
Estimated Afr/Ap 27 Apr 006/006
Predicted Afr/Ap 28 Apr-30 Apr 005/005-004/005-004/005

VI. Geomagnetic Activity Probabilities 28 Apr-30 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