Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 23 August 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 235 Issued at 2200Z on 23 Aug 2013

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to
23/2100Z: 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
22/2207Z from Region 1828 (N14E26). There are currently 9 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 day one (24 Aug) and expected to
be low on days two and three (25 Aug, 26 Aug).

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: 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
593 km/s at 22/2215Z. Total IMF reached 7 nT at 22/2100Z. The maximum
southward component of Bz reached -5 nT at 22/2205Z. Electrons greater
than 2 MeV at geosynchronous orbit reached a peak level of 1857 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at unsettled to minor storm levels on day one (24 Aug), quiet to
minor storm levels on day two (25 Aug) and quiet to unsettled levels on
day three (26 Aug).

III. Event probabilities 24 Aug-26 Aug
Class M 10/05/01
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 23 Aug 124
Predicted 24 Aug-26 Aug 125/120/115
90 Day Mean 23 Aug 113

V. Geomagnetic A Indices
Observed Afr/Ap 22 Aug 011/014
Estimated Afr/Ap 23 Aug 014/016
Predicted Afr/Ap 24 Aug-26 Aug 020/025-019/020-011/012

VI. Geomagnetic Activity Probabilities 24 Aug-26 Aug
A. Middle Latitudes
Active 40/40/20
Minor Storm 25/30/05
Major-severe storm 05/10/01
B. High Latitudes
Active 10/05/15
Minor Storm 25/20/30
Major-severe storm 60/75/30