Viewing archive of Saturday, 11 May 2002

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 2002 May 11 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 131 Issued at 2200Z on 11 May 2002

IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z

Solar activity was at moderate levels. Region 9937 (S09W38) produced an M1/Sf flare at 11/1132 UTC with an associated Type II radio sweep of 415 km/s and minor discrete radio bursts. Increased magnetic complexity is apparent in this region with the hint of a delta forming in the dominant spot, seen in the trailing portion of spot cluster. Region 9934 (S17W59) was fairly active today, producing multiple C-class flares. The largest was a C3/Sf flare occurring at 11/1738 UTC. This region remains the most complex region on the disk. New Region 9950 (S06E44) produced a C2/Sf flare at 11/1650 UTC. Region 9949 (S16W06) is also a newly numbered region.
IB. Solar Activity Forecast
Solar activity is expected to be low to moderate. Regions 9934 and 9937 are both complex enough to produced M-class flare activity.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic field was at quiet to major storm levels. Data from the Advanced Composition Explorer (ACE) showed an increase in the solar wind speed from roughly 350 to 450 km/s beginning at approximately 11/0915 UTC. The north-south component of the interplanetary magnetic field remained strongly negative for several hours thereafter. A sudden impulse of 41 nT was observed at the Boulder Magnetometer at 11/1028 UTC. Major storm conditions were observed at high latitudes from 11/1100 through 11/1800 UTC. Uncertain as to the source(s) of the activity, although multiple CME's were seen in SOHO/LASCO imagery on the eighth and ninth. Source regions for CME's believed to have been from both the east and west limbs.
IIB. Geophysical Activity Forecast
The geomagnetic field activity is expected to be at predominantly quiet to unsettled levels. Isolated minor storm conditions may occur on day three of the forecast due to the M1/Sf flare that occurred at 11/1132 UTC.
III. Event Probabilities 12 May to 14 May
Class M60%60%50%
Class X15%15%05%
Proton10%10%01%
PCAFgreen
IV. Penticton 10.7 cm Flux
  Observed       11 May 188
  Predicted   12 May-14 May  190/195/190
  90 Day Mean        11 May 187
V. Geomagnetic A Indices
  Observed Afr/Ap 10 May  019/017
  Estimated     Afr/Ap 11 May  035/040
  Predicted    Afr/Ap 12 May-14 May  012/015-008/010-012/012
VI. Geomagnetic Activity Probabilities 12 May to 14 May
A. Middle Latitudes
Active25%20%25%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active30%20%30%
Minor storm10%05%10%
Major-severe storm05%01%05%

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