Viewing archive of Monday, 27 May 2002

Solar activity report

Report of Solar-Geophysical Activity 2002 May 27 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 147 Issued at 2200Z on 27 May 2002

IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z

Solar activity increased to moderate levels. Region 9957 (N10W73) produced an M2/2f flare at 27/1810 UTC associated with minor discrete radio emission. Gradual decay may have continued in this region, but it was difficult to tell given limb foreshortening effects. However, it appeared that a weak delta persisted within its northern cluster of spots. Region 9961 (S22W30) produced isolated subflares as it continued to decay. Region 9970 (N05E41) appeared to stabilize as a simply-structured D-type spot group. Active surging and subflare activity was observed on the southeast limb near SE17. This limb activity may indicate the active return of old Region 9934 (S16, L = 211). A filament erupted from the northeast quadrant around midday. The eruption was associated with C2 X-ray event and a CME off the northeast limb. The CME did not appear to be Earth directed.
IB. Solar Activity Forecast
Solar activity is expected to be low to moderate. There is a fair chance for an isolated M-class flare during the period. There is a slight chance for a major flare as well.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
Geomagnetic field activity increased to quiet to active levels with minor storm conditions observed at some high latitude stations. This activity was likely due to coronal hole effects. ACE solar wind data indicated a gradual rise in velocities during the period with peak velocities in the 700 to 800 km/sec range.
IIB. Geophysical Activity Forecast
Quiet to active conditions are expected during the first half of the period. Quiet to unsettled conditions are expected during the remainder of the period. There is a slight chance for a proton event until 29 May.
III. Event Probabilities 28 May to 30 May
Class M40%40%40%
Class X05%05%01%
IV. Penticton 10.7 cm Flux
  Observed       27 May 187
  Predicted   28 May-30 May  180/180/180
  90 Day Mean        27 May 183
V. Geomagnetic A Indices
  Observed Afr/Ap 26 May  009/010
  Estimated     Afr/Ap 27 May  017/025
  Predicted    Afr/Ap 28 May-30 May  012/012-008/008-008/008
VI. Geomagnetic Activity Probabilities 28 May to 30 May
A. Middle Latitudes
Minor storm15%10%10%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm20%12%12%
Major-severe storm01%01%01%

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