Viewing archive of Tuesday, 23 April 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 Apr 23 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 113 Issued at 2200Z on 23 Apr 2002

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

Solar activity remained at low levels. Minor growth occurred in Regions 9914 (N04E18), 9915 (N11E28), and 9916 (S18E47) and each produced an isolated subflare. Region 9912 (N11W38) showed gradual decay in its trailer spots. A large filament erupted from the southwest quadrant during 22/2230 - 2325 UTC. A CME followed the eruption, but it did not appear to be Earth-directed. New Regions 9920 (S23W03), 9921 (N12E41), and 9922 (N19E56) were numbered.
IB. Solar Activity Forecast
Solar activity is expected to be low to moderate. There's a chance for an isolated low-level M-class flare during the period.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
Geomagnetic field activity ranged from quiet to major storm levels. Field activity increased to active to major storm levels during 23/0300 - 0900 UTC following a sudden impulse at 23/0450 UTC (60 nT, as measured by the Boulder USGS magnetometer). This increase was due to a CME passage associated with the X1 limb flare on 21 April from old Region 9906 (S16, L = 151). Activity decreased to unsettled to active levels during 23/0900 - 1800 UTC. The field was quiet after 23/1800 UTC. The greater than 100 MeV proton event that began at 21/0155 UTC ended at 22/2335 UTC (peak 22.9 pfu at 21/1025 UTC). The greater than 10 MeV proton event that began at 21/0225 UTC continued (peak 2520 pfu at 21/2320 UTC). The greater than 10 MeV flux at the close of the period was around 110 pfu.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at unsettled to active levels on 24 April decreasing to quiet to unsettled levels for the rest of the period. The greater than 10 MeV proton event is expected to end on 25 April.
III. Event Probabilities 24 Apr to 26 Apr
Class M40%40%40%
Class X05%05%05%
Proton99%80%20%
PCAFin progress
IV. Penticton 10.7 cm Flux
  Observed       23 Apr 175
  Predicted   24 Apr-26 Apr  180/180/180
  90 Day Mean        23 Apr 198
V. Geomagnetic A Indices
  Observed Afr/Ap 22 Apr  008/012
  Estimated     Afr/Ap 23 Apr  018/022
  Predicted    Afr/Ap 24 Apr-26 Apr  015/015-010/010-008/008
VI. Geomagnetic Activity Probabilities 24 Apr to 26 Apr
A. Middle Latitudes
Active40%30%25%
Minor storm10%05%05%
Major-severe storm05%01%01%
B. High Latitudes
Active45%35%30%
Minor storm15%10%10%
Major-severe storm10%05%05%

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