Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 21 August 2013

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 233 Issued at 2200Z on 21 Aug 2013

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to
21/2100Z: 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
21/0743Z from Region 1828 (N15E41). There are currently 10 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 (22
Aug, 23 Aug, 24 Aug).

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic
field has been at unsettled to active levels for the past 24 hours.
Solar wind speed, as measured by the ACE spacecraft, reached a peak
speed of 568 km/s at 21/1904Z. Total IMF reached 11 nT at 21/0205Z. The
maximum southward component of Bz reached -10 nT at 21/0215Z. Protons
greater than 10 MeV at geosynchronous orbit reached a peak level of 2
pfu at 21/1330Z. Electrons greater than 2 MeV at geosynchronous orbit
reached a peak level of 4274 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected
to be at quiet to active levels on days one and two (22 Aug, 23 Aug) and
unsettled to active levels on day three (24 Aug).

III. Event probabilities 22 Aug-24 Aug
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 21 Aug 130
Predicted 22 Aug-24 Aug 130/125/120
90 Day Mean 21 Aug 113

V. Geomagnetic A Indices
Observed Afr/Ap 20 Aug 005/004
Estimated Afr/Ap 21 Aug 015/018
Predicted Afr/Ap 22 Aug-24 Aug 011/012-014/015-016/020

VI. Geomagnetic Activity Probabilities 22 Aug-24 Aug
A. Middle Latitudes
Active 25/30/40
Minor Storm 05/10/20
Major-severe storm 01/01/05
B. High Latitudes
Active 15/15/10
Minor Storm 25/30/25
Major-severe storm 30/45/55