Viewing archive of Thursday, 21 April 2011
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 2011 Apr 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 111 Issued at 2200Z on 21 Apr 2011IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z Solar Activity has been at low levels for the past 24
hours. Region 1195 (S17E43) has been the most active region
producing multiple C-class events, the largest being a C8/Sf at
21/0948Z. Region 1193 (N16W32) remains magnetically complex, but has
yet to produce any notable activity. Region 1197 (S16E57) was
numbered early in the period and has remained stable and quiet.
IB. Solar Activity Forecast
Solar activity is expected to be at
low levels with a slight chance for M-class activity for the next
three days (22-24 April).
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field has been at quiet levels for the past 24 hours.
The effects of the latest coronal hole high-speed stream continue to
wane. Solar wind speeds, as measured by the ACE spacecraft, have
decreased from 500 - 440 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at mostly quiet levels for the next three days (22-24
April).
III. Event Probabilities 22 Apr to 24 Apr
| Class M | 20% | 20% | 20% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 21 Apr 113 Predicted 22 Apr-24 Apr 115/115/115 90 Day Mean 21 Apr 105
V. Geomagnetic A Indices
Observed Afr/Ap 20 Apr 011/016 Estimated Afr/Ap 21 Apr 005/005 Predicted Afr/Ap 22 Apr-24 Apr 008/008-005/005-005/005
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 05% | 05% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 05% | 05% |
| Minor storm | 05% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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