Viewing archive of Monday, 26 July 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 Jul 26 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 208 Issued at 2200Z on 26 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 25-2100Z to 26-2100Z

Solar activity was moderate. Region 652 (N08W47) produced two M-class flares - an M1/Sf at 26/0552Z, and an M1/2n at 26/1730Z. This region continues in a slow decay phase, but still exceeds 1000 millionths of white light area coverage in a moderately complex beta-gamma-delta configuration. Growth was observed in newly numbered Region 654 (N07E38), but no activity of note has occurred. The remainder of the disk and limb was quiet.
IB. Solar Activity Forecast
Solar activity is expected to be moderate. Region 652 will likely produce further M-class activity and still maintains potential for a major flare.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
The geomagnetic field ranged from quiet to severe storm levels. The severe geomagnetic storm that occurred yesterday, continued into the early hours of this period. Major to severe geomagnetic storm periods were observed through 26/0300Z. Solar wind speed remained elevated from 500 to over 700 km/s, but IMF Bz was generally around zero from 0300Z through the end of the period. Consequently, the geomagnetic field was mostly quiet to unsettled. The greater than 10 MeV proton event that began yesterday at 25/1855Z, is still in progress. The peak so far was 271 pfu at 26/1905Z. The greater than 2 MeV electrons at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to range from quiet to major storm levels. A full halo CME was observed on LASCO imagery following yesterday's long duration M1 flare at 25/1514Z. This CME will likely impact the geomagnetic field early on 27 July. Expect minor to major storm periods at all latitudes and severe storm levels at high latitudes. The storm is expected to end by 28 July. Mostly unsettled to active conditions are expected on 28 July. A return to quiet to unsettled levels is expected on 29 July with isolated high latitude active periods possible. The greater than 10 MeV proton event in progress now will likely end on 28 July.
III. Event Probabilities 27 Jul to 29 Jul
Class M65%65%50%
Class X15%10%10%
IV. Penticton 10.7 cm Flux
  Observed       26 Jul 128
  Predicted   27 Jul-29 Jul  125/120/115
  90 Day Mean        26 Jul 105
V. Geomagnetic A Indices
  Observed Afr/Ap 25 Jul  064/122
  Estimated     Afr/Ap 26 Jul  020/040
  Predicted    Afr/Ap 27 Jul-29 Jul  060/055-025/030-015/020
VI. Geomagnetic Activity Probabilities 27 Jul to 29 Jul
A. Middle Latitudes
Minor storm40%20%10%
Major-severe storm40%10%05%
B. High Latitudes
Minor storm30%25%15%
Major-severe storm50%15%05%

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