Viewing archive of Tuesday, 21 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 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 141 Issued at 2200Z on 21 May 2002IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z
Solar activity was low during the past 24 hours.
Today's largest event was a C4/Sf from Region 9960 (N14E35). A
comparison of white light and magnetogram data indicate that this
region has a small delta configuration. Region 9961 (N14E35) also
produced some C-class subflares today and shows a compact delta in
the leading part of the group. Region 9957 (N09E08) continues to be
the largest group on the disk and also possesses a delta. However,
this region was quiet and stable today, and is beginning to show
signs of decay.
IB. Solar Activity Forecast
Solar activity is expected to be
moderate during the next three days. The most likely sources for
energetic flare activity are 9957 and 9961, although 9960 could
contribute an isolated M-class event. There is a slight chance for
an X-class flare or proton producing event.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was mostly quiet to unsettled. There was one
period of active conditions from 0600-0900 UTC at high latitudes.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be predominantly quiet to unsettled for the next three
days. There is a slight chance for some isolated active periods on
day two (due to the CME of 19/2026 UTC) and on day three due to
possible coronal hole effects.
III. Event Probabilities 22 May to 24 May
| Class M | 70% | 70% | 70% |
| Class X | 20% | 20% | 20% |
| Proton | 15% | 15% | 15% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 21 May 186 Predicted 22 May-24 May 180/180/175 90 Day Mean 21 May 184
V. Geomagnetic A Indices
Observed Afr/Ap 20 May 008/014 Estimated Afr/Ap 21 May 008/010 Predicted Afr/Ap 22 May-24 May 005/010-012/012-012/010
VI. Geomagnetic Activity Probabilities 22 May to 24 May
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 25% | 35% |
| Minor storm | 10% | 15% | 15% |
| Major-severe storm | 05% | 10% | 10% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 25% |
| Minor storm | 10% | 20% | 35% |
| Major-severe storm | 05% | 20% | 10% |
All times in UTC
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