Viewing archive of Sunday, 28 July 2002

Solar activity report

Report of Solar-Geophysical Activity 2002 Jul 28 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 209 Issued at 2200Z on 28 Jul 2002

IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z

Solar activity decreased to moderate levels. Region 39 (S15W04) produced an M2/Sf flare at 28/0035 UTC as well as occasional C-class flares. No significant changes occurred within Region 39. It remained large and magnetically complex with strong, persistent delta configurations within its leading and trailing spots. Region 44 (S21W11) produced isolated C-class flares during the period. Slight decay was noted in the leading and trailing portions of the region. However, it became slightly more magnetically complex as new flux emerged that strengthened the delta within its intermediate spots. Region 50 (S07E09) was in a rapid growth phase and produced isolated subflares. New Regions 52 (N09E17), 53 (S17E24), and 54 (S21E70) were numbered.
IB. Solar Activity Forecast
Solar activity is expected to be at moderate to high levels. M-class flares are likely from Regions 39 and 44. Either region could produce a major flare during the period. Region 50 could produce an isolated M-class flare during the period.
IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z
Geomagnetic field activity ranged from quiet to active levels, possibly due to a weak negative-polarity high-speed stream. The greater than 10 MeV proton flux at geosynchronous orbit remained enhanced and continued to gradually decrease toward background levels.
IIB. Geophysical Activity Forecast
A geomagnetic field disturbance is expected to begin early on 29 July and continue into 30 July in response to the M8/halo-CME event of 26 July. Active to major storm levels are possible during this disturbance. Field activity is expected to decrease to quiet to unsettled levels on 31 July. Region 39 or 44 may produce a proton flare during the period.
III. Event Probabilities 29 Jul to 31 Jul
Class M80%80%80%
Class X30%30%30%
IV. Penticton 10.7 cm Flux
  Observed       28 Jul 239
  Predicted   29 Jul-31 Jul  245/245/240
  90 Day Mean        28 Jul 165
V. Geomagnetic A Indices
  Observed Afr/Ap 27 Jul  011/019
  Estimated     Afr/Ap 28 Jul  010/015
  Predicted    Afr/Ap 29 Jul-31 Jul  025/030-018/020-010/010
VI. Geomagnetic Activity Probabilities 29 Jul to 31 Jul
A. Middle Latitudes
Minor storm20%10%05%
Major-severe storm10%05%01%
B. High Latitudes
Minor storm25%15%10%
Major-severe storm15%10%01%

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