Viewing archive of Monday, 12 April 2004

Solar activity report

Report of Solar-Geophysical Activity 2004 Apr 12 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 103 Issued at 2200Z on 12 Apr 2004

IA. Analysis of Solar Active Regions and Activity from 11-2100Z to 12-2100Z

Solar activity was at low levels. Region 588 (S15W68) produced multiple C-class flares today. The largest was a C2/Sf event that occurred at 12/0225Z. This region remains a reverse polarity beta magnetic configuration. Updated LASCO imagery indicates two separate occurrences of CME activity yesterday. A partial halo CME was observed in response to the C9/Sf event (erupted at 11/0419Z) that indicates potential for a glancing blow from the likeliness of a resulting shock passage. The second, a full halo CME first seen in C2 at 11/1154Z, was determined to be backsided. New Region 591 (S15E01) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be at very low to low levels.
IIA. Geophysical Activity Summary 11-2100Z to 12-2100Z
The geomagnetic field was at quiet to active levels. A shock passage was observed at the ACE spacecraft at approximately 12/1730Z and it is believed to be in response to the partial halo CME that was associated with the C2 flare that occurred on 09/2040Z. Once again, the IMF Bz remained predominantly northward and the geomagnetic response was weak. Solar wind speeds peaked at near 540 km/s shortly after the shock passage and has decreased to approximately 440 km/s at the time of this writing. The greater than 10 MeV proton event that began at 11/1135Z, peaked at 35 pfu at 11/1845Z, and ended at 12/0405Z. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to range from quiet to active levels. Minor storm conditions may occur on 13 April in response to a shock passage from yesterdays C9 flare and the associated partial halo CME. 14 and 15 April should see a return to predominantly unsettled levels with the potential for active conditions, mostly in high latitude nighttime sectors.
III. Event Probabilities 13 Apr to 15 Apr
Class M15%15%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       12 Apr 091
  Predicted   13 Apr-15 Apr  095/100/105
  90 Day Mean        12 Apr 109
V. Geomagnetic A Indices
  Observed Afr/Ap 11 Apr  006/008
  Estimated     Afr/Ap 12 Apr  012/012
  Predicted    Afr/Ap 13 Apr-15 Apr  015/020-012/015-010/012
VI. Geomagnetic Activity Probabilities 13 Apr to 15 Apr
A. Middle Latitudes
Minor storm15%10%10%
Major-severe storm10%05%05%
B. High Latitudes
Minor storm20%15%10%
Major-severe storm10%10%05%

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