Joint USAF/NOAA Report of Solar and Geophysical Activity 24 Sep 2003
SDF Number 267 Issued at 2200Z on 24 Sep 2003
IA. Analysis of Solar Active Regions and Activity from 23/2100Z
to 24/2100Z: Solar activity has been low. Region 464 (N04E22)
continues to be the most active region. It has increased in
activity over the last 24 hours, producing a series of minor C-class
flares, and elevating the solar X-ray background to approximately
the B5 level. A 20-degree disappearing solar filament lifted off at
0532 UTC centered near S19W23. No new regions were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to remain
low. There’s a slight chance for M-class activity from Region 464.
IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field has been at unsettled to minor storm levels. A
geoeffective coronal hole has maintained a high-speed solar wind
stream, and sustained elevated geomagnetic field activity for the
last couple of days. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at unsettled to minor storm levels for the next day.
Beginning approximately in the next 36 hours, the solar wind speeds
should begin to relax in response to the passing of the coronal
hole. But, within the next two days, the disappearing solar
filament ejecta should impact the geomagnetic field causing a rapid
increase in activity to minor storm levels with isolated periods of
major storming possible.
III. Event Probabilities 25 Sep-27 Sep
- Class M 40/40/40
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 24 Sep 134
- Predicted 25 Sep-27 Sep 135/130/130
- 90 Day Mean 24 Sep 120
V. Geomagnetic A Indices
- Observed Afr/Ap 23 Sep 010/017
- Estimated Afr/Ap 24 Sep 030/020
- Predicted Afr/Ap 25 Sep-27 Sep 015/020-015/015-020/030
VI. Geomagnetic Activity Probabilities 25 Sep-27 Sep
A. Middle Latitudes
- Active 30/30/35
- Minor storm 20/20/25
- Major-severe storm 05/05/10
B. High Latitudes
- Active 40/35/40
- Minor storm 25/25/40
- Major-severe storm 20/10/20