Joint USAF/NOAA Report of Solar and Geophysical Activity 26 Dec 2004
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2004 Dec 26 2210 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 361 Issued at 2200Z on 26 Dec 2004
IA. Analysis of Solar Active Regions and Activity from 25/2100Z
to 26/2100Z: Solar activity was very low. Region 713 (S08W47)
produced a B9.9 flare at 26/1240Z. Region 713 is still in a decay
phase. A long duration B4.3 flare was observed on SXI imagery at
26/1929Z from a spotless plage region at S16E40.
IB. Solar Activity Forecast: Solar activity is expected to be very
low with a chance for isolated C-class activity from Region 713.
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:
The geomagnetic field was quiet to unsettled. The solar wind speed
is still elevated around 500 km/s due to the continued influence of
a geoeffective high speed coronal hole stream.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to unsettled with a chance for isolated active
periods at high latitudes on 27 December. Expect quiet to unsettled
on 28 and 29 December.
III. Event Probabilities 27 Dec-29 Dec
- Class M 05/05/05
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 26 Dec 092
- Predicted 27 Dec-29 Dec 090/090/090
- 90 Day Mean 26 Dec 104
V. Geomagnetic A Indices
- Observed Afr/Ap 25 Dec 006/012
- Estimated Afr/Ap 26 Dec 008/010
- Predicted Afr/Ap 27 Dec-29 Dec 008/010-006/008-005/005
VI. Geomagnetic Activity Probabilities 27 Dec-29 Dec
A. Middle Latitudes
- Active 20/15/15
- Minor storm 10/10/10
- Major-severe storm 01/01/01
