Joint USAF/NOAA Report of Solar and Geophysical Activity 19 Sep 2003
SDF Number 262 Issued at 2200Z on 19 Sep 2003
IA. Analysis of Solar Active Regions and Activity from 18/2100Z
to 19/2100Z: Solar activity was low. There were two C-class flares
during the past 24 hours. The first was a C2 at 18/2151 UTC which
appears to have originated from a region behind the east limb near
S06. The second was a C1 at 1820 UTC which was associated with
activity in Region 461 (N17E21). Region 461 continues to be the
largest region on the disk. Region 459 (S11W27) is showing slow,
steady growth and possesses a predominantly East-West inversion
line.
IB. Solar Activity Forecast: Solar activity is expected to be low
for the next three days.
IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:
The geomagnetic field ranged from active to minor storm levels during
the past 24 hours. This activity was due to the continued influence
of a high speed solar wind stream associated with a favorably
positioned coronal hole. Solar wind velocity has shown a slow
decline over the past 24 hours, with initial values around 800 km/s
having decreased to day-end values around 675 km/s.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly active with some isolated minor storm periods
for the next two days as the current disturbance persists. A decline
to unsettled to slightly active is expected by the third day.
III. Event Probabilities 20 Sep-22 Sep
- Class M 10/10/10
- Class X 01/01/01
- Proton 01/01/01
- PCAF green
IV. Penticton 10.7 cm Flux
- Observed 19 Sep 111
- Predicted 20 Sep-22 Sep 110/115/115
- 90 Day Mean 19 Sep 120
V. Geomagnetic A Indices
- Observed Afr/Ap 18 Sep 029/040
- Estimated Afr/Ap 19 Sep 025/035
- Predicted Afr/Ap 20 Sep-22 Sep 020/025-020/025-015/015
VI. Geomagnetic Activity Probabilities 20 Sep-22 Sep
A. Middle Latitudes
- Active 40/40/25
- Minor storm 25/25/20
- Major-severe storm 05/05/05
B. High Latitudes
- Active 30/30/35
- Minor storm 30/30/25
- Major-severe storm 20/20/10
