Joint USAF/NOAA Report of Solar and Geophysical Activity 23 Aug 2004

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.

Updated 2004 Aug 23 2210 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 236 Issued at 2200Z on 23 Aug 2004

IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was very low. B-class flares were
observed in Regions 661 (N07W60), 663 (N11E26), and 664 (S11W03).
Regions 661 and 664 are simple beta groups that exhibited little
change over the past 24 hours. Region 663, in a beta-gamma
configuration, is more complex, but has decayed slightly this
period. Remaining active regions were stable or in decay.

IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. There is a small chance for a C-class flare.

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field was quiet to unsettled. The IMF Bz was
predominantly southward; however, solar wind speed has declined to
near 400 km/s . The greater than 2 MeV electron flux at
geosynchronous orbit was at high levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels. Isolated active periods
are possible at high latitudes.

III. Event Probabilities 24 Aug-26 Aug

• Class M 10/10/10
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 23 Aug 110
• Predicted 24 Aug-26 Aug 110/105/095
• 90 Day Mean 23 Aug 110

V. Geomagnetic A Indices

• Observed Afr/Ap 22 Aug 008/013
• Estimated Afr/Ap 23 Aug 010/010
• Predicted Afr/Ap 24 Aug-26 Aug 010/015-008/012-008/010

VI. Geomagnetic Activity Probabilities 24 Aug-26 Aug

A. Middle Latitudes

• Active 20/15/15
• Minor storm 05/01/01
• Major-severe storm 01/01/01

B. High Latitudes

• Active 25/20/20
• Minor storm 10/05/05
• Major-severe storm 01/01/01