Joint USAF/NOAA Report of Solar and Geophysical Activity 24 Aug 2003

SDF Number 236 Issued at 2200Z on 24 Aug 2003

IA. Analysis of Solar Active Regions and Activity from 23/2100Z
to 24/2100Z: Solar activity was at low levels. Region 436 (N08W26)
produced a C1/1f flare at 24/0417Z. Region 436 has shown some weak
positive polarities in the trailing spots and some weak point
brightings. There has been no significant activity and relatively
little change in the other active regions since yesterday.

IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels. Region 436 has the potential for C-class
activity and a slight chance of M-class activity.

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field was at unsettled to minor storm levels. One
period of minor storm conditions was observed at 24/1500Z. At
24/0000Z solar wind speed decreased to 600 km/s and has continued a
gradual decline to 550 km/s by the end of the summary period. Bz
continues to fluctuate between +/- 6 nT.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to active conditions on day one of the
period. Quiet to unsettled conditions are expected on day two and
day three.

III. Event Probabilities 25 Aug-27 Aug

• Class M 15/15/15
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 24 Aug 116
• Predicted 25 Aug-27 Aug 115/115/120
• 90 Day Mean 24 Aug 127

V. Geomagnetic A Indices

• Observed Afr/Ap 23 Aug 026/044
• Estimated Afr/Ap 24 Aug 020/035
• Predicted Afr/Ap 25 Aug-27 Aug 020/030-015/020-015/015

VI. Geomagnetic Activity Probabilities 25 Aug-27 Aug

A. Middle Latitudes

• Active 50/35/35
• Minor storm 20/10/10
• Major-severe storm 01/01/01

B. High Latitudes

• Active 50/40/30
• Minor storm 30/25/15
• Major-severe storm 15/10/05