Viewing archive of Sunday, 19 September 2004
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2004 Sep 19 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 263 Issued at 2200Z on 19 Sep 2004IA. Analysis of Solar Active Regions and Activity from 18-2100Z to 19-2100Z
Solar activity was moderate. Region 672 (N05W58), which
has been in a decay phase over the last 72 hours, produced two
notable events this period. The first was an extended C3.8 flare at
19/1148Z that erupted along a filament channel just north of the
spot cluster. The second was an M1.9 flare at 19/1712Z. This
impressive flare had associated Type II (604 km/s) and Type IV radio
sweeps; a 520 sfu Tenflare, and a greater than 10 MeV proton event.
LASCO imagery was unavailable. Region 672 is a C-type beta spot
group with under 100 millionths of white light area coverage. Region
673 (S13E22) showed little change this period and continues to
produce occasional B-class flare activity.
IB. Solar Activity Forecast
Solar activity is expected to be low
to very low. There is a small chance of another M-class flare from
Region 672 before it rotates around the west limb early on 22
September. Occasional C-class flares are possible from Region 673.
IIA. Geophysical Activity Summary 18-2100Z to 19-2100Z
The geomagnetic field was quiet. Solar wind speed was generally below
400 km/s. A greater than 10 MeV proton event followed today's M1
flare at 19/1712Z. The proton event began at 19/1925Z and was still
in progress at the time of issue. The maximum flux value so far was
35 pfu at 19/2025Z. A greater than 100 MeV proton flux enhancement
was also observed, but has not exceeded the 1 pfu event threshold.
The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to remain at mostly quiet to unsettled levels on 20 and 21
September. A disturbance associated with today's M1 flare and CME is
expected to occur on 22 September: Active to minor storm periods are
likely. The greater than 10 MeV proton event in progress now is
expected to end by 21 September.
III. Event Probabilities 20 Sep to 22 Sep
| Class M | 15% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 99% | 10% | 10% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 19 Sep 105 Predicted 20 Sep-22 Sep 100/095/090 90 Day Mean 19 Sep 112
V. Geomagnetic A Indices
Observed Afr/Ap 18 Sep 016/016 Estimated Afr/Ap 19 Sep 005/008 Predicted Afr/Ap 20 Sep-22 Sep 005/008-008/012-015/020
VI. Geomagnetic Activity Probabilities 20 Sep to 22 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 20% | 30% |
| Minor storm | 01% | 05% | 10% |
| Major-severe storm | 01% | 01% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 25% | 40% |
| Minor storm | 05% | 10% | 20% |
| Major-severe storm | 01% | 01% | 10% |
All times in UTC
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