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

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 232 Issued at 2200Z on 20 Aug 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 C1 event observed at
20/0129Z from Region 1818 (S05W76). There are currently 7 numbered
sunspot regions on the disk.

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

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z: 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 472 km/s at
19/2209Z. Electrons greater than 2 MeV at geosynchronous orbit reached a
peak level of 5339 pfu.

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

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

IV. Penticton 10.7 cm Flux
Observed 20 Aug 132
Predicted 21 Aug-23 Aug 130/125/125
90 Day Mean 20 Aug 113

V. Geomagnetic A Indices
Observed Afr/Ap 19 Aug 006/005
Estimated Afr/Ap 20 Aug 003/004
Predicted Afr/Ap 21 Aug-23 Aug 015/018-014/015-009/012

VI. Geomagnetic Activity Probabilities 21 Aug-23 Aug
A. Middle Latitudes
Active 35/30/30
Minor Storm 10/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/15/15
Minor Storm 30/30/30
Major-severe storm 45/35/35