Joint USAF/NOAA Report of Solar and Geophysical Activity 17 Mar 2003
SDF Number 076 Issued at 2200Z on 17 Mar 2003
IA. Analysis of Solar Active Regions and Activity from 16/2100Z
to 17/2100Z: Solar activity was high. Region 314 (S16W39) produced
an X1/1b flare at 17/1905 UTC. The flare was accompanied by a 520
sfu radio burst at 2695 MHz. This region also produced several
C-class events over the past 24 hours. Sunspots continued to grow
and the delta configuration in the trailer spots had intensified
since yesterday. Other disk regions were relatively quiet.
IB. Solar Activity Forecast: Solar activity is expected to be
moderate. M-class activity is likely in Region 314, including the
possibility of another major flare.
IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z:
The geomagnetic field ranged from unsettled to major storm levels
under the influence of a coronal hole high-speed stream. Solar wind
speeds remained above 600 km/s and Bz fluctuated between +/- 10 nT.
The greater than 2 MeV electron flux at geosynchronous orbit was
high.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly active over the next 24 hours with the
possibility of minor storm periods. Activity levels are expected to
abate by the end of the three-day forecast period.
III. Event Probabilities 18 Mar-20 Mar
- Class M 50/50/50
- Class X 05/05/05
- Proton 05/05/05
- PCAF red
IV. Penticton 10.7 cm Flux
- Observed 17 Mar 125
- Predicted 18 Mar-20 Mar 130/130/125
- 90 Day Mean 17 Mar 138
V. Geomagnetic A Indices
- Observed Afr/Ap 16 Mar 012/023
- Estimated Afr/Ap 17 Mar 025/040
- Predicted Afr/Ap 18 Mar-20 Mar 020/020-015/015-012/015
VI. Geomagnetic Activity Probabilities 18 Mar-20 Mar
A. Middle Latitudes
- Active 50/40/40
- Minor storm 10/10/10
- Major-severe storm 05/01/01
B. High Latitudes
- Active 60/50/50
- Minor storm 20/15/15
- Major-severe storm 10/05/05
