Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Sep 2003
SDF Number 264 Issued at 2200Z on 21 Sep 2003
IA. Analysis of Solar Active Regions and Activity from 20/2100Z
to 21/2100Z: Solar activity was low. Today’s activity consisted of
occasional low-level C-class flares. Most of these were from Region
464 (N03E62) which is the largest group on the disk with an area of
430 millionths. The other regions on the disk were quiet and stable.
IB. Solar Activity Forecast: Solar activity is expected to be low.
There is a slight chance for an isolated M-class flare from Region
464.
IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field ranged from quiet to active levels, with a
period of minor storm at high latitudes from 1200-1500 UTC. High
speed solar wind from a coronal hole continues to drive the
activity. However, there was a gradual decline in wind speeds from
initial values of 650 km/s to day-end values of about 500 km/s. The
greater than 2 MeV electron flux was at high levels during the past
24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active for the next three days.
III. Event Probabilities 22 Sep-24 Sep
- Class M 20/20/20
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 21 Sep 120
- Predicted 22 Sep-24 Sep 125/125/120
- 90 Day Mean 21 Sep 120
V. Geomagnetic A Indices
- Observed Afr/Ap 20 Sep 034/025
- Estimated Afr/Ap 21 Sep 020/020
- Predicted Afr/Ap 22 Sep-24 Sep 015/020-015/020-015/020
VI. Geomagnetic Activity Probabilities 22 Sep-24 Sep
A. Middle Latitudes
- Active 35/35/35
- Minor storm 20/20/20
- Major-severe storm 05/05/05
B. High Latitudes
- Active 30/30/30
- Minor storm 25/25/25
- Major-severe storm 10/10/10
