Joint USAF/NOAA Report of Solar and Geophysical Activity 28 Dec 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Dec 28 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 363 Issued at 2200Z on 28 Dec 2004
IA. Analysis of Solar Active Regions and Activity from 27/2100Z
to 28/2100Z: Solar activity increased to low levels today. The
plague field in Region 713 (S09W78) showed a significant increase in
coverage along with the production of multiple C-class flares today,
the largest was a C7/1f event that occurred at 28/0010Z. An
increase in sunspot area and an increase in magnetic complexity were
observed this period. Region 715 (N04E74) began to rotate into view
and was numbered today. It is already exhibiting a large
asymmetrical sunspot. This region was responsible for the C7/Sf
event that occurred at 28/1801Z.
IB. Solar Activity Forecast: Solar activity is expected to be at
low levels.
IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field was at predominantly quiet to unsettled levels.
An isolated active period was observed between 28/1800 and 2100Z,
likely due to a sustained southward Bz which was observed by the
ACE spacecraft.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominantly quiet to unsettled throughout the
period.
III. Event Probabilities 29 Dec-31 Dec
- Class M 15/15/10
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 28 Dec 105
- Predicted 29 Dec-31 Dec 110/115/115
- 90 Day Mean 28 Dec 104
V. Geomagnetic A Indices
- Observed Afr/Ap 27 Dec 006/007
- Estimated Afr/Ap 28 Dec 007/010
- Predicted Afr/Ap 29 Dec-31 Dec 005/008-006/008-004/008
VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec
A. Middle Latitudes
- Active 15/15/15
- Minor storm 01/01/01
- Major-severe storm 01/01/01
B. High Latitudes
- Active 20/20/20
- Minor storm 05/05/05
- Major-severe storm 01/01/01
