Joint USAF/NOAA Report of Solar and Geophysical Activity 26 Oct 2003
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2003 Oct 26 2240 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 299 Issued at 2200Z on 26 Oct 2003
IA. Analysis of Solar Active Regions and Activity from 25/2100Z
to 26/2100Z: Solar activity has been high. Region 486 (S15E31)
produced a long-duration X1.2/3n at 26/0654 UTC, with associated
Type II and IV radio sweeps and a partial-halo CME observed on LASCO
imagery with an estimated speed of 1245 km/s. Region 484 (N03W41)
produced a long-duration X1.2/2n at 26/1819 UTC with an associated
Type II radio sweep and a partial-halo CME observed on Mauna Loa
coronameter imagery. The rise in X-ray flux for this flare was
observed at 1721, and 10 MeV proton flux began to rise at the ACE
spacecraft at 1750 UTC. The greater than 10 MeV proton flux at
geosynchronous orbit reached 10 pfu at 1825 and peaked at 332 pfu at
2020 UTC. An 18-degree filament erupted around S18W51 at 0346 UTC,
and a 12-degree filament erupted at N00W55 at 0331 UTC. Both
erupting filaments were observed on EIT imagery, and their
respective CMEs were observed on LASCO imagery. Neither CME appears
to be earth-directed. Regions 484 and 486 maintained their magnetic
complexity, although Region 484 decayed slightly in size. The 10.7
cm flux value was flare-enhanced and is estimated due to solar
activity at the time of the observation.
IB. Solar Activity Forecast: Solar activity is expected to be high.
Regions 484 and 486 are expected to produce C- and M-class flares,
and X-class flares are possible.
IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:
The geomagnetic field has been quiet to active.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet to active all three days, with possible minor
and isolated major storm conditions on days two and three due to
partial halo CMEs from both X flares observed today.
III. Event Probabilities 27 Oct-29 Oct
- Class M 90/90/90
- Class X 50/50/50
- Proton 25/25/25
- PCAF in progress
IV. Penticton 10.7 cm Flux
- Observed 26 Oct 298
- Predicted 27 Oct-29 Oct 200/200/170
- 90 Day Mean 26 Oct 121
V. Geomagnetic A Indices
Observed Afr/Ap 25 Oct 010/014
Estimated Afr/Ap 26 Oct 008/015
Predicted Afr/Ap 27 Oct-29 Oct 010/015-015/020-015/015
VI. Geomagnetic Activity Probabilities 27 Oct-29 Oct
A. Middle Latitudes
- Active 25/35/35
- Minor storm 20/25/30
- Major-severe storm 05/15/25
B. High Latitudes
- Active 30/35/30
- Minor storm 25/40/45
- Major-severe storm 20/30/30
