Viewing archive of Sunday, 11 April 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 Apr 11 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 102 Issued at 2200Z on 11 Apr 2004IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z Solar activity was low. Region 588 (S15W55) produced a
C9/1F flare and an associated filament eruption at 11/0419Z.
Moderate centimetric radio bursts accompanied this flare including a
920 sfu tenflare. A greater than 10 MeV proton event that began at
11/1135Z is also believed to be associated with this eruption. A CME
was observed on LASCO imagery and a preliminary analysis indicates
that while most of the ejecta is directed south and west, there is
an Earthward directed component. Region 588 is still the only
sunspot group on the visible disk and maintains a reverse polarity
beta magnetic configuration.
IB. Solar Activity Forecast
Solar activity is expected to be low
to very low. Region 588 may produce isolated C-class flares.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic field was quiet to unsettled. Solar wind speed began
the period at elevated levels (over 500 km/s) following yesterday's
shock arrival at 10/1925Z. However, IMF Bz stayed predominantly
northward and as a result, the geomagnetic disturbance was weak.
Solar wind speed dropped to around 430 km/s by the end of the
period. A greater than 10 MeV proton event began at 11/1135Z. The
peak so far was 35 pfu at 11/1845Z.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to range from quiet to minor storm levels. A CME associated
with the C2 flare at 09/2040Z is expected to produce occasional
active periods on 12 April. Mostly quiet to unsettled conditions are
expected on 13 April. Active conditions with high latitude minor
storm periods are expected on 14 April in response to today's C9
flare and CME. The greater than 10 MeV proton event in progress now
is expected to end on 12 April.
III. Event Probabilities 12 Apr to 14 Apr
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 75% | 10% | 05% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 11 Apr 090 Predicted 12 Apr-14 Apr 095/100/105 90 Day Mean 11 Apr 109
V. Geomagnetic A Indices
Observed Afr/Ap 10 Apr 010/010 Estimated Afr/Ap 11 Apr 010/012 Predicted Afr/Ap 12 Apr-14 Apr 012/015-010/015-018/025
VI. Geomagnetic Activity Probabilities 12 Apr to 14 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 35% |
| Minor storm | 15% | 10% | 20% |
| Major-severe storm | 05% | 05% | 10% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 35% | 30% | 40% |
| Minor storm | 20% | 15% | 25% |
| Major-severe storm | 10% | 05% | 15% |
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