Viewing archive of Friday, 23 July 2004

Solar activity report

Report of Solar-Geophysical Activity 2004 Jul 23 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 205 Issued at 2200Z on 23 Jul 2004

IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z

Solar activity has been moderate. Region 652 (N08W10) produced a C1.0 flare at 23/1609 UTC, which would not be noteworthy except that a full-halo CME was observed on LASCO imagery at the same time, as well as a Type II radio sweep with a speed of 710 km/s. Analysis of SXI and EIT imagery indicate that the flare and CME are probably associated. Region 652 also produced three M-class flares over the period, the largest an M2.2/Sf at 23/1728 UTC. A CME with a plane-of-sky speed of 700 km/s associated with this flare was observed on LASCO imagery. Region 652 maintains its large size and magnetic complexity. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be moderate to high. Region 652 may still produce major flares.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
The geomagnetic field has been at active to major storm levels from the continued effects of CME transient activity. After maintaining a mostly southward orientation for over 24 hours, Bz rotated northward at 1600 UTC. ACE solar wind speed has steadily declined to 500 km/s. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to active tomorrow (24 July) as the current activity subsides. A CME observed on 22 July may produce active and isolated minor storm conditions on 24 July. Activity should decrease to unsettled levels on 25 July. CME activity associated with today's C1 and M2 flares will likely impact Earth's geomagnetic field on 26 July, with active to minor storm conditions possible.
III. Event Probabilities 24 Jul to 26 Jul
Class M70%70%70%
Class X20%20%20%
IV. Penticton 10.7 cm Flux
  Observed       23 Jul 165
  Predicted   24 Jul-26 Jul  160/160/150
  90 Day Mean        23 Jul 104
V. Geomagnetic A Indices
  Observed Afr/Ap 22 Jul  013/019
  Estimated     Afr/Ap 23 Jul  040/050
  Predicted    Afr/Ap 24 Jul-26 Jul  020/025-015/015-025/025
VI. Geomagnetic Activity Probabilities 24 Jul to 26 Jul
A. Middle Latitudes
Minor storm20%10%20%
Major-severe storm10%05%10%
B. High Latitudes
Minor storm30%25%30%
Major-severe storm15%10%15%

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