Joint USAF/NOAA Report of Solar and Geophysical Activity 31 Jul 2004

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

Updated 2004 Jul 31 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 213 Issued at 2200Z on 31 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 30/2100Z
to 31/2100Z: Solar activity was at low levels today. Old Region 652
(N08, L=348) has rotated further beyond the western solar limb and
yet was responsible for the most significant activity observed
today. Region 652 produced a C8 x-ray flare that peaked at 31/0657Z
and had an associated CME as seen on LASCO imagery that does not
appear to have an Earth directed component. Region 654 (N08W28)
showed some decay today in spot area coverage and produced a lesser
B-class flare. No new regions were numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
very low to low levels.

IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field was at quiet to unsettled levels. The greater
than 2 MeV electron flux at geosynchronous orbit reached very high
levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels throughout the period.

III. Event Probabilities 01 Aug-03 Aug

• Class M 05/05/05
• Class X 01/01/01
• Proton 01/01/01
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 31 Jul 086
• Predicted 01 Aug-03 Aug 085/085/085
• 90 Day Mean 31 Jul 106

V. Geomagnetic A Indices

• Observed Afr/Ap 30 Jul 007/007
• Estimated Afr/Ap 31 Jul 007/010
• Predicted Afr/Ap 01 Aug-03 Aug 008/008-005/008-005/005

VI. Geomagnetic Activity Probabilities 01 Aug-03 Aug

A. Middle Latitudes

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

B. High Latitudes

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