Joint USAF/NOAA Report of Solar and Geophysical Activity 20 Dec 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Dec 20 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 355 Issued at 2200Z on 20 Dec 2004
IA. Analysis of Solar Active Regions and Activity from 19/2100Z
to 20/2100Z: Solar activity was very low. Region 713 (S09E34) has
grown in white light area coverage to over 200 millionths and has
developed a magnetic beta-gamma configuration. No new regions were
numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low. Region 713 could possibly produce an isolated C-class
event.
IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was quiet. 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 quiet to unsettled. Isolated active periods are
possible on 22 December due to the influence of a recurrent coronal
hole high speed solar wind stream.
III. Event Probabilities 21 Dec-23 Dec
- Class M 15/15/15
- Class X 01/01/01
- Proton 01/01/01
- PCAF Green
IV. Penticton 10.7 cm Flux
- Observed 20 Dec 094
- Predicted 21 Dec-23 Dec 100/100/105
- 90 Day Mean 20 Dec 104
V. Geomagnetic A Indices
- Observed Afr/Ap 19 Dec 001/004
- Estimated Afr/Ap 20 Dec 003/004
- Predicted Afr/Ap 21 Dec-23 Dec 008/010-015/020-010/012
VI. Geomagnetic Activity Probabilities 21 Dec-23 Dec
A. Middle Latitudes
- Active 15/25/20
- Minor storm 05/10/10
- Major-severe storm 01/05/01
B. High Latitudes
- Active 20/30/25
- Minor storm 10/20/15
- Major-severe storm 05/05/05
