Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 20 July 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 201 Issued at 2200Z on 20 Jul 2013

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to
20/2100Z: 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
20/0338Z from Region 1793 (N21W01). There are currently 3 numbered
sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be very low
with a chance for a C-class flares and a slight chance for an M-class
flare on days one, two, and three (21 Jul, 22 Jul, 23 Jul).

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: The geomagnetic
field has been at quiet to unsettled levels for the past 24 hours. Solar
wind speed, as measured by the ACE spacecraft, reached a peak speed of
637 km/s at 19/2332Z. Electrons greater than 2 MeV at geosynchronous
orbit reached a peak level of 4162 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to unsettled levels on day one (21 Jul) and quiet levels
on days two and three (22 Jul, 23 Jul).

III. Event probabilities 21 Jul-23 Jul
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 20 Jul 113
Predicted 21 Jul-23 Jul 115/115/120
90 Day Mean 20 Jul 121

V. Geomagnetic A Indices
Observed Afr/Ap 19 Jul 013/017
Estimated Afr/Ap 20 Jul 006/007
Predicted Afr/Ap 21 Jul-23 Jul 008/008-004/005-004/005

VI. Geomagnetic Activity Probabilities 21 Jul-23 Jul
A. Middle Latitudes
Active 15/10/10
Minor Storm 05/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 25/20/20
Major-severe storm 20/10/10